Going to need more info, what version of windows, 32 or 64 bit, service pack and all that.
That error reported in whocrashed can be caused by a ton of different things. Bad sectors on the hard drive, bad memory, infections, bad drivers and so on.
So the best thing to do is to start going down a process of elimination until we find the cause.
First one is testing the hard drive for bad sectors and testing the memory. have you done that yet?
Shane