Is my graphics card reaching its end?

I have an early 2008 iMac 24" and am trying to figure out if the graphics card is failing. When I turn it on after having it off for a while I am able to log in fine, and then the screen at some point will turn a solid color of some kind such as purple, blue, gray or black. If I reboot it and try turning it on again it usually doesn't last as long as the last boot and so on.

I've got into safe mode a few times and it works perfectly and didn't freeze so thats why at first I suspected a software problem, but it could just be coincidence since it seems the computer will sometimes work or not.

Any advice on what could possibly be wrong?

Thanks ^_^

The next time the screen turns a solid color, take a screen shot of your desktop. If the screen shot shows the same thing, it's graphics related. If not, then it may be the LCD itself or software causing it.

If you're not experiencing the same problem in Safe Mode, it may well be software or a driver causing it.

I'm not able to take a screenshot since it freezes afterwards.
If it's a software/driver problem, how would I approach fixing it?

- I've also made an appointment with the Genius Bar for them to take a look at it, but if I can get it fixed my self that would be nice. I usually have negative experiences with the Genius Bar.

If your iMac is still under warranty (Apple care) then let your local genius bar take care of it. If its not under Apple care, make sure you get an estimate first. An iMac is a difficult machine to repair because it has to be opened first. That means removing the display and front panel.

Have you tried logging into another user account. If it functions correctly in the new account and not the current one that might suggest a software issue.

What does the Console show? Not that I'm an expert about that, but others I'm sure are.

Console is under Applications --> Utilities.

Then copy out from Log Files -> System log

Expertus said:

I'm not able to take a screenshot since it freezes afterwards.
If it's a software/driver problem, how would I approach fixing it?

- I've also made an appointment with the Genius Bar for them to take a look at it, but if I can get it fixed my self that would be nice. I usually have negative experiences with the Genius Bar.

Click to expand...

One thing you can try is to download the latest Update Combo available for your version of OS X and apply that. Sometimes this helps iron out bugs. If you have a driver that has become corrupted, the UC may replace it with a fresh copy.

The problem persists on all accounts, sometimes my computer freezes before it even gets to the log in screen.

I've also tried installing the latest combo update, still nothing.

As for the logs, I'm on my laptop at the moment because Safari on the iMac goes unresponsive after a minute or so.

Could it be a disk error or file system corruption?

I've experienced what you mentioned and I have a mid-2008 24" iMac.

All hard drives fail eventually, so I really hope you religiously back-up your system.

I was going to upgrade my internal hard drive, but ran into problems with 2 of the Western Digital ECO drives (1 Caviar Green & 1 Caviar Blue). I don't know why Mac OS didn't play well on them. I did format them and reinstalled OS X Snow Leopard and all my data from Time Machine.

I got tired of all the problems and I was in the middle of a big development project for a website so finally reverted to the original 320 GB disk. After formatting and re-installing I have not experienced that issue again for several months.

I can't say what the cause was for sure. But I've decided to upgrade to a new 27" iMac. (Which should arrive this Friday!) At least from the experience I am no longer afraid to take my iMac apart. I used to put together my own Windows PCs back before I started using the Mac at home. The iMac reminds me of laptops because of the tight spaces and layered components, just on a bigger scale.

I don't have an solution for you, but just thought I would throw this out there to see if you have considered it.

Hmm, thanks for the advice ^_^
Yea luckily I had my entire system backed up when I went off to school last August. Someone else said it may be a hard drive problem, though I'm beginning to suspect something on the lines of either the logic board or the graphics card.

I'm crossing my fingers on it not being the logic board, but yea I'm getting it checked out this Friday so wish me luck haha.