Computer crashing issues need help

[BurnoutSpartan]

I've been having some crashing issues on my computer lately. Whenever I launch games on my PC after 10 or so minutes my computer will black screen then shut off. Recently the problem started when I install the new WoW expansion to my computer and will now even crash in games like Left 4 Dead 2 or Team Fortress 2, but it happened a few months ago while playing Civilization 5. I thought it would be a RAM problem but every time I try to run Windows Memory Diagnostics it will black screen 3/4 the way through (always a good sign). Any help or fixes are appreciated below is my specs.

AMD Athlon II X2 245 Processor 2.9 GHz
4 GB RAM
Windows 7 Home Premium 64-bit OS
1 TB HDD (775 GB still available)
ATI Radeon HD 4650 1024 MB DDR2 PCI Express 2.0

don't have present motherboard information

 

[mlc]

1st.. i'd try reinstalling the graphics drivers...

2nd.. i'd try pulling the ram, and only run the diagnostics with 1 stick at a time..

if neither or those fix it.. then i'd consider getting your hands on a spare psu.. and try swapping that in....

 

[BurnoutSpartan]

I reinstalled the drivers but when I took one card out it still froze after the diagnostics and I couldn't turn on my computer for awhile...any other suggestions?

 

[mlc]

sounds like a weak psu.. if you have another pc around.. try swapping its psu into your machine..

It can also be the board itself.. graphics card or the memory.. but the fact that you said it worked after you waited a while. .would lead me away from the graphics card and the memory.. but it's hard to be 100% certain

 

[oynaz]

You say that the memory diagnostics black screens? As in crashes?

If yes, you probably have a piece of defective hardware, probably RAM, PSU or motherboard (from most to least probable, IMO).

 

[denis280]

What kind of power supply.What kind of memory.HDD Brand name.and Mobo?

 

[fire400]

rebuild os environment if you can't think of anything else after the tests.

can try free dos hardware tests if you think win7 is giving you trouble.

some BIOS's on mobos will have test options for RAM/HD.

check:1 thermal paste on cpu and graphics card, as well as sensor programs.

also, could be a messed up video card. try another graphics card, even if it's a low profile graphics card, you can still stress test it. if both graphics cards are acting up, might be the motherboard bridge, although this doesn't happen very often, in which case the motherboard is dying, and unless you have dual graphics card slots and then you can change the graphics card seating to another slot to see if it helps.