The hardest computer problem I've encountered so far is knowing the reason why my computer will always shutdown just after 10 minutes of turning it on.
Did you experience some worst/hardest computer problem? what is it?
war10ck2011, when I checked the power supply and replace it with new one, that's how I know what went wrong with my computer.
Then there comes a time my computer always hang or lag. Then I checked the cpu and found out that it was a processor heat problem caused by non-functional cpu fans. Then I replaced my cpu fans and walaaa, my computer worked great again.
I don't know other difficult computer problems. I think I didn't encounter them yet. Maybe you can share it to us.