Thanks HappyRock. My apologies for taking so long to follow through ... whenever I've had a spare moment the kids have been hogging the computer!
Here's the analysis from WhoCrashed. It looks like my anti-virus software is the main culprit.
Analysis
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Crash dump directory: C:\WINDOWS\Minidump
Crash dumps are enabled on your computer.
On Fri 19/03/2010 9:46:21 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xACCA5217, 0xA87FB798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini031910-02.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Fri 19/03/2010 5:37:42 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xACCA3217, 0xA975B798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini031910-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sun 14/03/2010 9:34:48 AM your computer crashed
This was likely caused by the following module: bckd.sys
Bugcheck code: 0x1000000A (0xE8, 0x2, 0x1, 0x806E6A16)
Error: Unknown
Dump file: C:\WINDOWS\Minidump\Mini031410-02.dmp
file path: C:\WINDOWS\system32\drivers\bckd.sys
On Sun 14/03/2010 6:36:29 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x10000050 (0x925AA327, 0x1, 0xACCC2217, 0x0)
Error: Unknown
Dump file: C:\WINDOWS\Minidump\Mini031410-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sat 13/03/2010 12:31:48 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xAC17D217, 0xA9731798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini031310-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Tue 9/03/2010 5:30:00 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xAC7B6217, 0xA9913798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini030910-02.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Tue 9/03/2010 5:15:31 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xABB49217, 0xA8F4D798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini030910-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sun 7/03/2010 9:34:21 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xAC6AD217, 0xB9960798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini030710-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sat 27/02/2010 3:45:33 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xAC731217, 0xBA187798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini022710-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Mon 22/02/2010 7:44:56 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xAC8B4217, 0xA8B63798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini022210-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Mon 15/02/2010 1:24:07 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xAC921217, 0xA87AA888, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini021510-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sun 14/02/2010 2:20:35 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xAC79C217, 0xA876F798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini021410-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Fri 12/02/2010 5:01:13 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xAC8CC217, 0xA97D6798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini021210-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Mon 25/01/2010 8:03:37 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xAC86F217, 0xA9AE6798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini012510-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sat 23/01/2010 8:12:29 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xAC829217, 0xA916E798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini012310-02.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sat 23/01/2010 6:33:26 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xAC829217, 0xA916E798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini012310-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sat 16/01/2010 10:09:02 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xAC7CB217, 0xA8700798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini011610-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sat 9/01/2010 2:45:37 AM your computer crashed
This was likely caused by the following module: bckd.sys
Bugcheck code: 0x1000008E (0xC0000005, 0x0, 0xA90448C0, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini010910-02.dmp
file path: C:\WINDOWS\system32\drivers\bckd.sys
On Sat 9/01/2010 2:38:59 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xABC30217, 0xA8B9A798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini010910-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Mon 28/12/2009 6:15:06 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xACC2B217, 0xA884E798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini122809-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sat 26/12/2009 10:47:48 PM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xACA87217, 0xA8754888, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini122609-02.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sat 26/12/2009 9:57:13 PM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xABBDB217, 0xA8568798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini122609-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Mon 14/12/2009 11:28:35 PM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xACC7A217, 0xA95E6888, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini121409-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sun 13/12/2009 2:41:13 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000000A (0xE8, 0x2, 0x1, 0x806E6A16)
Error: Unknown
Dump file: C:\WINDOWS\Minidump\Mini121309-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Fri 4/12/2009 9:43:52 PM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xAC95D217, 0xA90D9798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini120409-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Mon 30/11/2009 10:10:19 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000000A (0xE8, 0x2, 0x1, 0x806E6A16)
Error: Unknown
Dump file: C:\WINDOWS\Minidump\Mini113009-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sat 28/11/2009 5:08:03 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xACB3C217, 0xAA078798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini112809-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sat 21/11/2009 11:57:51 PM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xACD57217, 0xB982C798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini112109-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Thu 19/11/2009 2:03:51 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xACAE7217, 0xA9145798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini111909-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Mon 16/11/2009 2:06:32 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xABECB217, 0xA8B5F888, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini111609-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sat 14/11/2009 1:40:34 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xABE69217, 0xA8B8D798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini111409-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sun 25/10/2009 5:38:53 AM your computer crashed
This was likely caused by the following module: bckd.sys
Bugcheck code: 0x1000000A (0xE8, 0x2, 0x1, 0x806E6A16)
Error: Unknown
Dump file: C:\WINDOWS\Minidump\Mini102509-01.dmp
file path: C:\WINDOWS\system32\drivers\bckd.sys
On Thu 22/10/2009 11:40:53 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xABF3D217, 0xA9116798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini102209-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sat 17/10/2009 12:11:35 AM your computer crashed
This was likely caused by the following module: aswtdi.sys
Bugcheck code: 0x1000008E (0xC0000005, 0xABE2B217, 0xA8840798, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini101709-01.dmp
file path: C:\WINDOWS\system32\drivers\aswtdi.sys
product: avast! Antivirus System
company: ALWIL Software
description: avast! TDI Filter Driver
On Sat 8/11/2008 6:23:07 AM your computer crashed
This was likely caused by the following module: ati3duag.dll
Bugcheck code: 0x1000008E (0xC0000005, 0xBF248DD5, 0xA988AA08, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini110808-07.dmp
file path: C:\WINDOWS\system32\ati3duag.dll
product: ATI Technologies Inc. Radeon DirectX Universal Driver
company: ATI Technologies Inc.
description: ati3duag.dll
On Sat 8/11/2008 6:12:22 AM your computer crashed
This was likely caused by the following module: ati3duag.dll
Bugcheck code: 0x1000008E (0xC0000005, 0xBF248DD5, 0xA9B39A08, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini110808-06.dmp
file path: C:\WINDOWS\system32\ati3duag.dll
product: ATI Technologies Inc. Radeon DirectX Universal Driver
company: ATI Technologies Inc.
description: ati3duag.dll
On Sat 8/11/2008 5:57:52 AM your computer crashed
This was likely caused by the following module: ati3duag.dll
Bugcheck code: 0x1000008E (0xC0000005, 0xBF248DD5, 0x8BB87A08, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini110808-05.dmp
file path: C:\WINDOWS\system32\ati3duag.dll
product: ATI Technologies Inc. Radeon DirectX Universal Driver
company: ATI Technologies Inc.
description: ati3duag.dll
On Sat 8/11/2008 1:46:20 AM your computer crashed
This was likely caused by the following module: ati3duag.dll
Bugcheck code: 0x1000008E (0xC0000005, 0xBF248DD5, 0xA98EFA08, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini110808-04.dmp
file path: C:\WINDOWS\system32\ati3duag.dll
product: ATI Technologies Inc. Radeon DirectX Universal Driver
company: ATI Technologies Inc.
description: ati3duag.dll
On Sat 8/11/2008 1:40:29 AM your computer crashed
This was likely caused by the following module: ati3duag.dll
Bugcheck code: 0x1000008E (0xC0000005, 0xBF248DD5, 0xA9B66A08, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini110808-03.dmp
file path: C:\WINDOWS\system32\ati3duag.dll
product: ATI Technologies Inc. Radeon DirectX Universal Driver
company: ATI Technologies Inc.
description: ati3duag.dll
On Sat 8/11/2008 1:20:04 AM your computer crashed
This was likely caused by the following module: ati3duag.dll
Bugcheck code: 0x1000008E (0xC0000005, 0xBF248DD5, 0xA9C57A08, 0x0)
Error: KERNEL_MODE_EXCEPTION_NOT_HANDLED_M
Dump file: C:\WINDOWS\Minidump\Mini110808-02.dmp
file path: C:\WINDOWS\system32\ati3duag.dll
product: ATI Technologies Inc. Radeon DirectX Universal Driver
company: ATI Technologies Inc.
description: ati3duag.dll
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Conclusion
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41 crash dumps have been found on your computer. Only 40 could be analyzed. Note that it's not always possible to state with certainty whether a reported driver is really responsible for crashing your system or that the root cause is in another module. Nonetheless it's suggested you look for updates for the products that these drivers belong to and regularly visit Windows update or enable automatic updates for Windows. In case a piece of malfunctioning hardware is causing trouble, a search with Google on the bug check errors together with the model name and brand of your computer may help you investigate this further.