The first suspect is overclocking. The second possibility is some other hardware issue (usually a memory issue). The third possibility is a software conflict, nearly always with a security program (hard to see what business it is of a security program to go corrupting other processes memory space, but sadly it does happen).

If you need help finding some diagnostic tools, we keep a few useful links in the Start Here FAQ forum.

uuuhhh. Pushing the computer with some bios commands to run faster than it's set for. Some do. Some burn out. Some cause errors to the workunits if they run too fast. OK. You're not overclocking.

Time for a memory test. These crunchers usually push the computer hard, and are a good test in themselves. Now, to find the error. If you have more than 1 stick of memory, they can sometimes be incompatible. A memory tester will check all of those dusty areas of the chip that the operating system usually reserves for itself. Memtest86+ is one of the best ones out there, and it doesn't take too long to run, but must be done from a special boot floppy it makes.

http://en.wikipedia.org/wiki/Memtest86

I was expanding memory last year, and got 2 incompatible sticks --- TWICE. This thing helped me get a good pair that would work together.

Be sure to let the test run for several hours, preferrably overnight. One pass is often not enough to show any errors. Let us know how that goes and we can suggest corrective action or further testing.