Computer freezing up

[tadroptopgirl]

For the past few weeks after I transferred all of my internals to a new case and reinstalled a good and clean copy of windows 7. I have been getting intermediate problems with the display. I have a XFX Radeon 4650 for 3 years now and it has worked fine. But what it does on occasion is the screen will freeze with the back light lit and I have to restart it. Works fine after that for a while. And then when I am watching a movie it will slow down and the video will freeze but not the audio so it catches up eventually.

Gigabyte GA-990FXA-UD3
XFX Radeon 4650
AMD 965 Phenon 2 quad core 3.4ghz
Corsair 2x 4gbs ddr3 13333
4 western digitals ON-Board Raid array 5 1.81tbs
2 Seagate Baracuda 1 tb sata 1 OS sata 2 files
2 lg dvd writers
Thermaltake MK-1 Chaser case

 

[Engima]

Have you cleaned the dust out of your components?

 

[vrumor]

What PSU do you have?

 

[tadroptopgirl]

I cleaned all components when I put it in the new case

corsair 650 watt system.builder