You should run a memory tester like memtest on your PC. Download the zipped ISO and burn it as a CD image to a CD then boot off it. Just leave it running overnight.
Sounds good in theory... except see my other thread about my CD burner no longer burning CDs. It will burn DVDs, however, so I have burned it to a DVD and will see if I can boot off of that. I'll have to go into my BIOS and change the bootup sequence to start with the CD player...
I have an old memtest.exe file in my utilities folder that I ran, it made three passes with no errors, but of course it wasn't checking memory in use by Windows, and I'm not at all sure it was looking at all four gigabytes of RAM.
tanstaafl.