It really depends, it could be not as such hardware related but maybe the actualy computer software and drivers arnt working correctly...
Make sure you have the lastest drivers for your card.
I had an issue like this a little while ago, I ended up reformatting, the problem disappeared immediately.
A 200W PSU though...Seems scarily inadequate for any type of gaming these days.
If you are going to upgrade the Power Supply, do not get a $20 cheapie, or you will be very upset when in a months time, the computer doesn't work again. Get at least a $60-80 one.
@ kebubas:
I reformatted, reinstalled all the drivers, problem went away. So I don't actually know what caused my problem, but it was not hardware.