How can I prevent Processor Ovearheat?

I have a 3.0 ghz 800 fsb intel pentium 4 processor and well I was on vacation with my dad and when my cpu overheats it will turn off my computer but the problem is that I can boot up my computer but theres a little burn mark on the processor where you connect the processor at and I was wondering If I were to put thermal grease (it didn't have any before) will it work or will it still overheat.