Hello, I am hoping someone can shed some light on this problem I am having.. Quad G5.. all temps are normal. Apple Service diagnostic reports everything is fine. Apple Hardware Test reports no problems. PROBLEM: Went to install on a dedicated hard drive Tiger 10.4.2(original disk media which came with my G5). Installer succeeds and finishes.. Now the problem comes up as follows: Once I go and register my computer and setting up my account and password(all before the desktop), I get the spinning beach ball of death, along with the fans kicking in(not too extreme), forcing me to do a force shutdown. I then arrive at the desktop. All programs in the Applications folder run, EXCEPT for: ichat and skype. I try to click on ichat and skype and I see the spinning beach ball again.. I notice my CPUS are at 100 percent load due to loading up skype and or ichat. What is wrong with my Quad G5? I attempted to try another hard drive and the same thing happens. I tried a different video card(my original 7800 GT, replacing the 6600). This is indeed a very strange problem. Memory checks out fine and passes on both testing of apple service diagnostic and apple hardware test. I am out of options here.. what could the problem be? I am going to attempt to install the updates to Tiger and go to 10.4.11 and see if that solves the problem. I also did a similar test for Leopard - same issues. At this point I am a little concerned, though I know my LCS is operating within the normal limits and no LEDs are coming on, at least any, indicating a pump failure or overheat(GOD FORBID! as I just got this mint like unit from someone who has never ever had problems before). Zen, and others who know a lot about the G5 Quad, if you are out there.. this is one time I DO need some help. Thanks, Josh. P.S. AFAIK, I ran all major tests and nothing points to faulty hardware at all.. certainly someone out there knows what could be causing this. This has never happened to me before..