Crashes when playing games

What brand PSU?

Show us what exactly the PSU is?

If it's a low quality one or it has low amperages, replace the PSU, get something like this: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

I bought it about three years ago, there is no brand name it just says LPG6-50 550w.
I think it could be that the power supply doesnt have PCI e connectors.
The grapchics card connectors are plugged into normal connectors and not directly into the PSU.

Well that is not allowed when you don't plug the PCI-E connectors, that's why it's freezing. Or you mean you use adapters? Upgrade your PSU.

Yes ill get a better PSU thank you. Im even lagging in warcraft 3. :< Thank you for the fast reply

Im thinking about buying the Coolermaster RP/RS-650-PCAR eXtreme power plus 650w
What do you think?

You can go with better brands, how much is it?

dont buy that psu buy psu of powerful brands like corsair,antec,seasonic etc.

Oh God no.........

Look, the wattage claims mean nothing. It's all about amps on the +12v rail and efficiency. If the psu doesn't even have a basic 80+ efficiency certification, don't bother.

This is how psu's are classified:

CRappy 70%
80+ certified
80+ bronze
80+ silver
80+ gold
80+ platinum

That coolermaster is "crappy 70%".

The psu you have now likely put's out about 300-350w max, not 500w.

Where are you buying from and what is your psu budget?

The power supply is the most important component of the computer, yet I never understand why people trust their new high end parts to some generic piece of crap.