[kill bill]

a few hours ago, i had to restart my system after a minor crash. no big deal (or so i thought at first). Now every time i try to start up my computer, it stalls on the gray screen. There's an apple logo and a spinning gear and nothing else. i got on my other computer (this one) and looked up the troubleshooting stuff that apple provides (safe booting, disk utilities, peripherals, etc). i tried everything and nothing worked. Nothing happens when i hold down shift upon power, or when i hold c with the start up disc in. The only thing that worked was when i held down control + shift and c. it took me to a black screen with a bunch of white text. What can i do to get my computer to work again or to get it to respond to the stuff that's supposed to fix it

btw, its an imac (a little over a year old).

[Big Mac]

There's no such Mac OS X keyboard combination as control-shift-c.

Do this: On startup hold down command-s to boot into CLI single user mode. When you get to the prompt, type fsck -yf and press return. It will run through the filesystem repair and then will say FILESYSTEM MODIFIED. Run fsck -yf again two or three more times until instead of saying FILESYSTEM MODIFIED it says FILESYSTEM OK. Then type exit and press return. See if it boots that time. I don't know why you wouldn't be able to boot using the system disc and holding the c key.

[cgc]

The bootup key combinations are listed here. I looked around for others with similar problems and some have reported bad logic board, bad hard drive, or a weird hardware combo they were trying to make into a hackintosh that kept them stuck at the grey screen. Seems the grey screen might signify a hardware problem though I'd be interested to see a listing of what the colors symbolize during bootup.

[King Bob On The Cob]

Originally Posted by cgc 

The bootup key combinations are listed here. I looked around for others with similar problems and some have reported bad logic board, bad hard drive, or a weird hardware combo they were trying to make into a hackintosh that kept them stuck at the grey screen. Seems the grey screen might signify a hardware problem though I'd be interested to see a listing of what the colors symbolize during bootup.

White Screen with text: OpenFirmware command line

Solution: type "mac-boot" (NEVER TYPE "w"). Possibly bad keyboard? Zap PRAM. If that doesn't work, get a new computer, because it's quite possible that the motherboard is completely shot.

Grey screen with no apple - the EFI (Or OpenFirmware if you've got PPC) cannot boot the computer because the kernel will not start.

Solution: Zap the PRAM, if that doesn't work, Hard Drive failure is likely. Boot off the CD and see if you can repair the disk. Then backup your files and make sure you keep consistent backups (You do this anyways, right?), because often, if you see this error once, the drive is starting to go.

Black screen with text - you booted into verbose mode, or you booted into single user mode

Solution: Stop holding the keys down, or if you did not, clear the PRAM and NVRAM as needed.

Grey screen with apple and spinning - Kernel is booting, and you can drop it down to single user mode to see what's going on, and possibly run some command line stuff.

Solution: Boot off restore DVD and repair disk, then repair permissions and see if that works. It may require a re-install or bringing it to your friendly neighborhood Mac geek.

Blue Screen nothing else - windowserver or loginwindow is attempting to launch, but the kernel thinks it's done.

Solution: Caches or corrupt preferences are usually the culprit here. There's loads of write-ups out there, you will need to drop down to single user mode to clear them.

Once you're past there, you're gravy,

[cgc]

Mmmm...gravy...

[kill bill]

Well, on a whim I just left the computer alone during the boot and went to sleep. A few hours later, it was totally booted. I've been using it since but its behavior has been really peculiar. I am now having some serious issues with slowness and program instability. It's a night and day difference. Two days ago, everything was totally fine, now its like my computer is senile. What could have happened? Corrupted boot files?

KBOC, it seems like I was having the kernel problem you mentioned in your post. How do you fix that?

[cgc]

Can you boot from an OSX DVD? If so, you may need to do a reinstall...

[kill bill]

Originally Posted by cgc 

Can you boot from an OSX DVD? If so, you may need to do a reinstall...

Well, i can boot without it, but now it seems like the RAM in my computer just went stale. Basic things take much longer than before and my programs are prone to freezing.

[cgc]

There are apps out there that test your memory...I used memtest when I had issues. It ran at the command line (e.g. "single-user mode") before OSX booted