My iMac G5 PPC is going into sleep mode when surfing to some webistes like YouTube or othher sites where Flas or shockwave is needed. It's already our second iMac G5 PPC 17" within a few months. The first one had fan problems and monitoring it with iStats show temps of 80C and fanspeed of 5700 RPM. Working normal causes no problems but going to YouTube and look at a video is almost directly a problem. Any idea to solve this problem?