Another possible cheap fix I have used - check you cooling fans! I got the BSOD on mine because one of the internal fans wasn't running quite as fast as it used to. They do need periodic cleaning if they are in a dirty environment (under a desk, dusty, pet hair, etc). Every so often, the part of the mother board that slow fan was cooling would overheat and safety shutdown.

Had the exact same thing on my TIVO once. Was a $5.00 hardware fix that saved me from a complete failure by catching it before there was any permanent damage.