graphics card problem

i currently am running a at radeon 7000 on my Hp system with an amd 1.33ghz and 384mb of ram and random red dots appear everywhere on dark backgrounds and white dots appear when playing games or dvds. the problem is not in the drivers becuase i have tried all of ati’s and nothing seems to resolve the problem. maybe my graphics card doesnt get the cooling it needs because when i underclock it the problem occurs less. Can someone give me some suggestions on how to fix this? if you have any info please contact me at, thanks