You'll get StackHash module errors when windows couldn't identify the module it was in when the application crashed. In that case, the kernel simply takes a hash of the stack so at least we might be able to identify if you've seen this exact crash before.
I would start with a good 'ol Memory Checker, then update your drivers from there. Do you seem to see the error when in games mainly? Could indicate a graphics issue, try updating your video card drivers if that is the case.
Do you have DEP turned on for all programs by chance?