Everything started yesterday, after I upgraded my RAM. I replaced the old 2 sticks of 256MB with two new sticks of 512MB and one of the old 256. As soon as I started the machine back again it happened for the first time. Now it happens mainly when I'm playing WoW (the only game I'm playing lately)
Here is what Everest Home Edition is telling me about my system. Maybe it will help a bit.


My machine has a generic 400W PSU, one optic drive, one SATA 80GB HDD and an IDE 80GB HDD (ATA 133), a Radeon 9800SE and 3 case fans of 80mm as main power eaters.