The sound crackling happened quite abruptly, I can't recall doing anything to the machine that would warrent this happening. I performed a virus scan last night and found a trojan I couldn't remove:
C:\System Volume Information\_restore{35A4A879-B4E1-4F85-811E-93C3722DA63B}\RP113\A0022655.exe »NSIS »jkill.exe - Win32/ProcKill application
After the scan, I rebooted to find that my sound driver (Realtek AC97 3.78) has been uninstalled (I installed the driver from the company's website, so the driver isn't malicious). I reinstalled it only to find the same problem being here to stay.
Here is a hijackthis log:
Logfile of HijackThis v1.99.1
Scan saved at 10:22:48 AM, on 10/21/2005
Platform: Windows XP SP1 (WinNT 5.01.2600)
MSIE: Internet Explorer v6.00 SP1 (6.00.2800.1106)
Running processes:
C:\WINDOWS\System32\smss.exe
C:\WINDOWS\system32\winlogon.exe
C:\WINDOWS\system32\services.exe
C:\WINDOWS\system32\lsass.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\spoolsv.exe
C:\Program Files\Eset\nod32krn.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\System32\hkcmd.exe
C:\WINDOWS\mHotkey.exe
C:\Program Files\Java\jre1.5.0_01\bin\jusched.exe
C:\Program Files\Eset\nod32kui.exe
C:\WINDOWS\SOUNDMAN.EXE
C:\Program Files\Nikon\PictureProject\NkbMonitor.exe
C:\Program Files\Stardock\ObjectDock\ObjectDock.exe
C:\WINDOWS\System32\svchost.exe
C:\Program Files\BitComet\BitComet.exe
C:\Program Files\Miranda IM\miranda32.exe
C:\Program Files\Rainmeter\Rainmeter.exe
C:\Program Files\Soulseek\slsk.exe
C:\Program Files\Java\jre1.5.0_01\bin\jucheck.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\Documents and Settings\dan\My Documents\software\hijackthis\HijackThis.exe
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://www.emachines.com/
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://www.emachines.com
O2 - BHO: AcroIEHlprObj Class - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Adobe\Acrobat 5.0\Reader\ActiveX\AcroIEHelper.ocx
O3 - Toolbar: &Radio - {8E718888-423F-11D2-876E-00A0C9082467} - C:\WINDOWS\System32\msdxm.ocx
O4 - HKLM\..\Run: [HotKeysCmds] C:\WINDOWS\System32\hkcmd.exe
O4 - HKLM\..\Run: [CHotkey] mHotkey.exe
O4 - HKLM\..\Run: [HPDJ Taskbar Utility] C:\WINDOWS\System32\spool\drivers\w32x86\3\hpztsb07.exe
O4 - HKLM\..\Run: [SunJavaUpdateSched] C:\Program Files\Java\jre1.5.0_01\bin\jusched.exe
O4 - HKLM\..\Run: [nod32kui] "C:\Program Files\Eset\nod32kui.exe" /WAITSERVICE
O4 - HKLM\..\Run: [SoundMan] SOUNDMAN.EXE
O4 - HKCU\..\Run: [MSMSGS] "C:\Program Files\Messenger\msmsgs.exe" /background
O4 - HKCU\..\Run: [Microsoft Works Update Detection] C:\Program Files\Microsoft Works\WkDetect.exe
O4 - HKCU\..\Run: [AIM] C:\Program Files\AIM\aim.exe -cnetwait.odl
O4 - Startup: Stardock ObjectDock.lnk = C:\Program Files\Stardock\ObjectDock\ObjectDock.exe
O4 - Global Startup: NkbMonitor.exe.lnk = C:\Program Files\Nikon\PictureProject\NkbMonitor.exe
O8 - Extra context menu item: &Google Search - res://c:\program files\google\GoogleToolbar2.dll/cmsearch.html
O8 - Extra context menu item: Backward Links - res://c:\program files\google\GoogleToolbar2.dll/cmbacklinks.html
O8 - Extra context menu item: Cached Snapshot of Page - res://c:\program files\google\GoogleToolbar2.dll/cmcache.html
O8 - Extra context menu item: Similar Pages - res://c:\program files\google\GoogleToolbar2.dll/cmsimilar.html
O8 - Extra context menu item: Translate into English - res://c:\program files\google\GoogleToolbar2.dll/cmtrans.html
O9 - Extra button: AIM - {AC9E2541-2814-11d5-BC6D-00B0D0A1DE45} - C:\Program Files\AIM\aim.exe
O14 - IERESET.INF: START_PAGE_URL=http://www.emachines.com
O20 - Winlogon Notify: igfxcui - C:\WINDOWS\SYSTEM32\igfxsrvc.dll
O23 - Service: iPod Service (iPodService) - Apple Computer, Inc. - C:\Program Files\iPod\bin\iPodService.exe
O23 - Service: NOD32 Kernel Service (NOD32krn) - Eset - C:\Program Files\Eset\nod32krn.exe
Thank you in advance for your help.