over the last 2 or 3 days, i've had a number of problems with my powerbook g4. yesterday, for example, i came home from work to check my ims. when i did, the screen looked normal, that is, until i clicked on instant messenger. when i did this, the screen turned to this funny blue-ish hue. then, i couldn't click on things. the mouse moved around and worked like a charm but for the life of me i couldn't click on anything. later on that nite, my computer started making a loud, constant whirring noise. it sounded like the fan was going insane. worked normally for most of today. about an hour ago, my computer froze up again. i had to restart 10 or 12 times before i was able to successfully reboot. the diagnostic cd that came with my mac says everything is in tip top shape, as does norton antivirus. any suggestions?