Computer shuts off while gaming no warning

[Pbpro9988]

I have an issue with my computer. Mostly when playing game on my computer ill get about 5-10 min of gameplay before my computer will just shutoff with no warnings what so ever. I can leave my computer on ideling for days or anytime i want to surf the internet with no issues, but if I start gaming, it will shut off. I had the computer built about 3.5 years ago so after the first 1-2 times this happened, i decided to open it up and give it a good spray cleaning. It seemed like this helped for about a month but its happening more frequently.

I installed Core Temp 1.0 and get temperatures that float around 95F surfing the web and about 115F gaming, is it a heating issue then?


Specs
OS
Windows 7 Professional
CPU
AMD Anthlon II x3 435 @2.9 GHz

RAM
G. Skill 4 GB dual channel DDR3 @669.7 MHz (I think, im not exactly sure if i im reading the specs right)

Motherboard
Gigabyte GA-MA770T-UD3P AM3 AMD 770 ATX AMD Motherboard

Graphics
Radeon HD 4870

PSU
Corsair TX650w


If you need any more info just ask....

Thanks

 

[bartholomew]

115F is just 46c. It doesn't seem to be overheating.
Its probably the PSU that's giving out under load.
See if you can borrow a friend's PSU, to test it out.

 

[amuffin]

Have you tried memtest86 on your ram?

 

[abekl]

If it were memory he'd be getting a blue screen, not a shut off.

 

[Rugger]

Have you checked your system event log to see what error codes you're getting on shutdown? Modify your system behavior so you get a BSOD on system error. Instructions for both:
To modify the restart behavior for the computer, follow these steps:
- Right-click My Computer, and then click Properties.
- Click Advanced system settings.
- Click the Advanced tab.
- In the Startup and Recovery section, click Settings.
- Click to clear the Automatically restart check box.

This will let you get the BSOD when your computer reboots/shuts down. To check for errors on previous shut downs you can check the system event log:
- Click the Start button .
- In the Search box, type Event Viewer and hit enter
- In the list of results, double-click Event Viewer.

 

[eggbrook]

It could still very likely be a ram issue, I had this happen before. It would blue screen me so fast that I wouldn't even see it. Run memtest, you'd be surprised what ram errors will cause.

 

[Pbpro9988]

So i went ahead and replaced the power supply, i bought this one http://www.newegg.com/Product/Product.aspx?Item=N82E16817139020

ive never replaced a power supply before so basically as i was disconnecting the old plugs i was plugging in the new ones plugs in. So i got everything all together, closed the case up, and plugged all the wires into the back. I flipped the switch on the power supply to the on position and turned the tower on. I could see on my monitor it was booting up but when it was about to get to the login screen, the screen stayed black and never went anywhere after that...