Hello, I am a basement studio producer who recently purchased a Mac Mini Intel Duo 1.66Ghz 60Gig HD with 512RAM off Ebay. Mac OSX pre-installed by the seller. Being a thrifty consumer I also purchased 2GB RAM 667Mhz which I immediately installed after working with the 512 RAM for a few days. After I installed the memory things were dandy, I was running itunes from MP3 off my External SATA drives (I still had from my recently closed Window days). I wasn't really pushing the memory envelope b/c I have outboard equipment for that. Anyway, I installed the memory and checked it on Thursday (it appeared fine)... Sunday the system started up. I did some web surfing (nothing major) and decided to close up but the OSX would not shutdown upon my election of it in the drop down window. During this 45 minute period, the USB farthest inward (out of the four) began to malfunction as well (the usb was connected to a mixer and the connection had worked previously but now the sound was coming from the mini's speakers). It would also not sleep or log off. And the twirling kaleidescope went on incessantly. I did a disk utility check and the HD checked out but the check for the mounting drive only yielded the same twirling kaleidescope. Again, I unplugged it and replugged it. It started up without a glitch, safari worked and closed out but as soon as i clicked on About this mac or shutdown, etc. No dice. I then removed the new memory and inserted the old memory. Still no shutdown, no log off (it did open about this mac and showed its configuration). Then the kaleidescope came back and I had to shut it down again (by pulling the plug)... also the usb port that was malfunctioning seemed to work. Can anyone point me to what might be going wrong? Thanks, cause your guess is good as mine!!! It doesn't appear broken as much as maybe a system download may have corrupted it but again I don't know.