Purple lines randomly drawn!

[ebow]

Please chime in if you know anything about this--it's such a weird problem...

Recently, I've been getting strange magenta lines that are randomly drawn across parts of my display. The strangest thing is, if they appear across part of an image that I'm editing, they can get saved in that image file. This would seem to mean that they're not just artifacts that get drawn to the display, but are more "real," being drawn at the OS's display level.

I have a CRT iMac running OS X 10.2.6. I've been using an appearance theme called Rhapsodized for many months before this problem began appearing.

Over the same general period of time, my computer's been getting a lot less stable; apps will "unexpectedly quit," sometimes repeatedly (particularly Apple-made ones, though IE is a big culprit here). And then, out of nowhere, the screen goes blue, all apps quit, and the Finder relaunches. I can't think of any single app that I installed that could be causing all this, but to be honest, I just moved and couldn't vouch for what I've installed over the past few months.

Here are some screenshots I've taken, demonstrating the problem:

Across 3 columns in the Finder
Another one across 3 columns in the Finder
Across the center of my desktop background
Across the center of an installer's dialog box
Across the title of a dialog box's title bar
Across a menu bar and title bar
Across my Safari bookmarks bar
Across a submenu of my Apple menu

Has anyone ever seen anything like this? Do you think it's a hardware or software problem? I'll be trying some tests, like booting OS 9, logging in as a guest, etc. to see if I can learn anything. But otherwise, I'm ready to take it in for service (one month of AppleCare left), or reformat the whole HD, or both!

 

[Rower_CPU]

That's pretty out there. Have you tried repairing permissions lately?

You also might look at your display drivers and make sure they are up-to-date and not corrupted. A driver re-install might be in order.

 

[Gus]

Take it in, now. That looks like a video card problem, and it won't get better on its own. If you have only one month of AC, then take it in while you still can.

Regards,
Gus

 

[scem0]

yeah that doesn't look like a problem that you can do anything about software-wise.

I think you will have to mess around inside the machine, but you shouldn't do that if you don't know what you're doing. So I would take it in.

scem0

 

[ebow]

I've figured it a hardware thing, except I didn't expect to be able to catch it in screenshots if it's purely hardware. As for reinstalling video drivers, well, how do I do that? I'm no computer dummy, but it's never been something I've had to think about with an iMac before.

Anyway, I might as well have it looked at for free while I can. This computer needs to hold me over until the G5 PowerBooks or the 2nd-gen PowerMac G5s are out next spring.

Update (long after fixing the problem): the repair guys replaced my logic board, but the problems persisted. They also told me that one stick of RAM (512MB alas) was bad and once I replaced it the lines and other problems went away. So the lesson is... never forget to consider RAM as a potential source of bizarre problems.