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.