I've killed my PC. PLEASE HELP!!

It's a P4 2.8ghz.

I've got the standard whopping big fan on the chip with that crystal paste over the chip but that's normal I guess. On the back of the case is another fan sucking hot air out.

 

Exactly, as soon as i got my CPU it was a quick windows set-up with security then benchmarking software and i began overclocking, same when i upgraded to a new motherboard and also same when i got a graphics card.

I'm not one of these people who can afford to get the best components all the time so i get the absolute best i can and then overclock to get some extra performance.