[markwilliamson2001]

Do you have two memory sticks? Try removing one of them, then see how she runs for a while... If it still happens, then try the other one.

Easiest way is to get a linux boot disc, and run memtest on it. That will tell you if there is a problem! Try the boot disc with the above test to see if one of your sticks is dodgy. The other reason you get BSOD's is driver updates....
Have you done any driver updates of late?

Try rolling back any drivers you recently updated and give that a whirl as well.
Hope this helps.