hey guys... i got problem here..
my fren G4 got graphic problem.. it run run run then suddenly the screen change to rainbow colour..
and sometime dono suddenly turnoff..

may i know what the cause of this issue? i hav tried to update the latest AMD ATI driver but the situation keep on happen..

any experience before?? isn overheat so hav this problem??

and can let me know what software to check on the temperature and this and that?? thx..