I was having this issue in Windows XP and thought to resolve it by running Windows XP x64. Same issues.
Since the problems have started, the following components have been changed out : Motherboard (Twice), RAM (Now using PNY 512MB stick), Video Card, Hard Drive, CPU, Sound Card, DVD drive, and network card. All of the drivers have been updated to current with the exception of the built in network card which stays current motherboard release.
I have run memtest v3.62 5 times without a failure.
The errors happen randomly, once eve while I was trying to register for this forum, several times if I am not a the desk, some times in the middle of a game.
I am starting to suspect the power supply, although that was replaced 2 motherboards ago.
P.S. The hard drives have been wiped before each OS Install and OS's are installed fresh.