Need help, Computer keeps freezing when play games

Alright when i play some games my computer freezes like 5 min into it, this has only happend with three of my games 1 warcraft 3, 2 train simulator and 3 rome total war i play alot of high end graphic games like just cause 2 frontlines and cod and it goes smooth as and i also play css and gmod its perfectly fine with all of em except a few.

All the games are off steam and install correctly and my computer is perfectly fine ill give the specs anyway


intel(R) Core i5-2500 cpu @ 3.30ghz, 3301 mhz 4 core(s), 4 logical pro

8gb ram

nividia geforce gtx 560 ti 1gb

msi p67a-c43 motherboard intel p67 ddr3 2133mhz

antec 850watt wuattro true power supply

and my os is windows 7

so please help me, ill looked some stuff up on the net and said that i should clean up my registry ive downloaded multiple programs and done so and it still happends ive run about 2- 5 system maintenance programs and it still does it i am just stumped on what is wrong with my computer