first off all, what PSU, motherboard/CPU and graphics card do you have?
when did the issue start happening, or has it always happend since you first had the computer (how long have you had the computer)
was it a custom build you made yourself or is it a store bought computer (make/model if you know it)
if you dont know what components/motherboard/CPU/graphics card you have, try using this:
Speccy:
http://www.piriform.com/speccy
which should identify them.
have you checked on the manufacturers website to see if there is a known issue and a hotfix issued?







