I'm beginning to go slightly insane. I'm running a 2.16 Macbook, upgraded to Leopard and now running 10.5.1. I am getting the beachball when I try to do...well, pretty much anything in any program. Click a link in safari - the beachball appears and the whole system freezes up. Same with Firefox. Try to close a program - beachball appears, whole system freezes up. Play a song in iTunes - FREEEEEZE. Observing the activity monitor shows very little increase in CPU usage during these moments. I've tried verifying and repairing both the permissions and the internal HD. No errors. I'm beginning to think that perhaps I have a duff Macbook. Of course, boot camp running XP is flawless which makes me doubt that theory. I noticed the DivXNetworks thing but I presume that's just for PPC macs? Does anyone have any ideas at all? I'm finding myself using windows as I cannot bear the constant crashing on OSX!