If you fried your computer, then the computer should still start up, but you will here various beep patterns, and there wont be any video displayed.
It's hard to fry a motherboard or processor, the only way I can see that it would happen is if you install the processor wrong, you cause a short circuit on the motherboard either by not using the studs, using them where they dont belong, or spill something on the board.
If everything is working and all of a sudden stopped when the computer was closed up, it's probably because of something else.