I have a 2.2Ghz Macbook Pro 15" (2007) that suddenly can't get past the startup screen and ends up with a kernel panic and the You need to restart message. Happens 100% of the time now. I had Leopard on it when it started kernel panicking. I managed to boot from an external drive and installed Snow Leopard, but it started okay once or twice, then started having the kernel panics at startup again. Tried SMC reset, but no go. I then tried going back to Tiger, thinking it might be a problem with the RAM. Tiger actually installed okay, and after it worked okay for a bit (2-3 times, maybe half an hour), I tried to install Leopard again. And got only kernel panics. And I can't install Tiger now either. It occasionally starts up from an external disk that I use for installs (has Leopard and Snow Leopard on it), but that's not 100%. And I can't even get thru an install now. I started up with it in Firewire Disk mode, wiped the drive and cloned a system from my iMac, but even though it seemed to go okay, when I shut it all down and tried to restart the Macbook Pro, I got another kernel panic. Any ideas? I've switched 3-4 different RAM modules, and I don't think they're ALL bad. But no go. I've changed hard drives too. Seems weird. I mean, it doesn't seem broken, as it starts up, goes thru the startup screen, seems to pause a bit and, instead of going to login, stops with a kernel panic. I assume it's HARDWARE, not software. But hardware problems are usually the RAM, sometimes the hard disk; and if the MBPro doesn't start up at all, then the logic board is probably fried. So what else can cause these kernel panics? A bad keyboard/trackpad (top case)? Bad PRAM battery? Any help greatly appreciated.