Computer keeps shutting down when playing specified games

[@hmed]

I've got a strange problem:
My comp shuts down when i play Counter Strike, Counter Strike: Condition Zero and Starcraft. When I play anything else it doesn't.
My comp:
MB - MSI K9N SLI Platinum nForce 570 SLI chipset
Proc - Athlon X2 6000+ AM2 + Scythe Katana cooler
Ram - 2x GeiL 512 MB 667 MHz AND 2x OCZ Specjal Ops 1 GB 800 MHz
Graph - Asus 7900 GT TOP 256 MB
Power - 450 Watt (I forgot the brand)

Recently I changed the proc from AMD Athlon 64 3500+ and added the cooler.
Thats when it began shutting down. I havent overclocked any components.
Yesterday I opened the case and turned my pc on. I checked the temperature of all components and:
proc: 37C
graph: 39C
Chipset: 66-70C !!! - I read somewhere that it's typical for nForce 500 series to work hot, but 70C?!
Whats more, i made a processor stress test, it heated up to 50C, but the rest was fine and it didnt shut down.
Can that^ be the cause??? Or maybe the Power Supply???

 

[pdyckman@comcas]

It may be that these certain games are taxing your components more than the others. In this case you have to go through the trial and error method of discovery. Your PSU may be borderline. The only way to find out what the problem is: replace each component with a "known working part"...then play the game that is draining your machine. Also: 66-70C is extremely hot. I'm sure it's a contributing factor. (may be the entire problem). Keep it at or under 60.

 

[AlbertLionheart]

Your PSU is maybe a bit below spec but first I would make sure you have the latest set of drivers for the graphics cards - go to the Asus site for them.

 

[Tedster]

READ: https://www.techspot.com/vb/topic66073.html