Asus P5K-E not POSTing

[core2kid]

I have the Asus P5K-E that at random times will not POST. The computer will turn on and the fans will hit high speed and just freeze. No picture on the screen. I have to hold down the power or reset button until the computer turns off and turns back on to clear the CMOS and load default settings and it will then boot to Windows. Please help, this is getting really annoying.