Computer AHHHHHHHHHH -Freeze, no sig.-

[ProJecTX1]

I have an epox 8k7a with a tbird 1.4 non overlocked. I have a generic psu but it has been working good. But every little while my computer will stay on and freeze and there would be no signal to the monitor. When i turn it off it wont go back on until i hit the side of the computer itself.

Thanks allot