MacBookPro freezes in grey screen at start up, showing apple and windmill. Last week it froze in blue screen. After trying everything except wiping the disc (it wouldn't reinstall over 10.6.2, I kept getting a crash window), I tried Safe-start. That failed, but at the next attempt to start it normally it suddenly got past blue screen and booted. Now I'm not getting past grey screen. I've once again tried everything short of wiping the harddrive which I don't want to do since I've got some new stuff there that's not been backed up yet. So far: C-start to SL system disk Disk Utility/repair permissions + repair disk Apple Hardware test (No problems) Reset SMC/ reset PRAM Safe start I assume that 10.6 won't install over 10.6 without first erasing everything? But will that work? Any suggestions or explanations? Can I back up content through the SL OS disk, an external hard drive, before wiping the my harddrive and trying re-install? BTW, I had installed SL over Tiger on this old MBP using the inexpensive OS disc I bought at an authorized Apple dealer, using their advice. I'd be very grateful for help. I'm at my wits' end and feel like I have to buy a new laptop, but am reluctant to get another Mac.