Months ago, there was a windows XP update that I felt acted somewhat strage during installation, the following morning my computer would not boot at all. The only way to boot the computer was to remove the CMOS battery on the motherboard which I did. I then replaced the CMOS battery and my computer would boot fine. Obviously I lost all of my bios settings, but since I was did not build this machine and it was given as a gift I had no way of knowing the previous settings. I did reseat one piece of ram as well.
After a few days of use the computer started to Hard Freeze, total lock up no mouse, no access to task manager , speakers looping etc. It happens at random intervals on various applications at windows login, on desktop, in Firefox browser etc even with the system just sitting idle. Often if I turn off the surge protector overnight I get a "checksum" error on boot, but when leaving the power on I do not get the checksum error.
Things I have done with no results:
-Virus/Malware/Spyware scans, 6-7 programs - nothing found
-Took apart computer, reseated all components - no result
-Ran Memtest, and Memtest86 for 24 hours each - no errors
-Updated sound/video/LAN/ethernet drivers - no change
-Manually cleaned registry - no results
-Replaced CMOS Battery for a second time - no results
-Used Jumpers to clear/reset Bios - no change
-Monitored Computer Temperatures - 31C/34C
-Chkdisk/Disk Defragment - No errors, no change
-System Retore - no change
Phoenix/Award Bios v6.00PG
NF650islit-a ECS motherboard
Nvidia Geforce 7800 GTX 256mb video card.
Intel E4400 2.0ghz Duo
WDC WD16 00AAJS-00MOA SCSI hard drive.
Windows XP Home SP3
So to recap, I am getting a hard freeze issue which restarting is the only option. Full system lockup. The only event log item I get is a DHCP warning. I will give a more detailed system spec once I get back onto the rig in question. Any help and/or advice would be much appreciated.