IMac ghost display problems (and apple technicians weren't able to solve)

Question

Hi,
So my problem here is quite weird. I tried researching the forum for something like this, but nothing really came close to whats happening to my iMac.
I have an Intel-Based iMac, 24 inch screen.
I bought it on 2008. Since late 2008/early 2009, i had these weird "letters" underneath all my pictures. I work with photography/video editing, so this was very annoying, yet i kept ignoring, since the rest was working fine.
Then slowly the iMac ran slower, more sluggish-y. Like if all life was sucked out of it, sort of description.
Then, 2 months ago, there was a total failure of the HD. I was lucky to be able to back up all, before it didnt let me even enter the computer. It would just think for hours.
I brought it to the technical support near to my home, and i also told them about those weird "letters" on the left side of my screen. They said it was due to my hard disk, and i was, ok...since the hard disk had a failure.
They did a check up, and yep, the hard disk was k.o, evidently. They replaced the hard disk, and told me all was fine.
It did "seem" fine for the first couple days. No more running slow, no weird letters that would distort my pictures (for example, i could see my iTunes music list underneath a picture i was working on photoshop, or a video i was displaying!).
After a couple of days...same story started again. The left side of the screen was flooded by all underneath (open windows, the desktop icons, the texts i had open on safari, basically anything would appear translucently underneath any image or video i would open). Then, flash player would crash every 3 videos, blank cd's would get automatically ejected so i couldnt burn any cd, computer would run slow etc... etc...
So i cleaned up my computer, did a back up, erased all, and ready to bring it up to technical support again. And misteriously, all symptoms disappeared. So i explained to them what happened, and they said probably it was the graphic card.
I thought finally my problem was solved.
24 hrs later, i got an email that my computer was fixed. That it was only a hard disk "permits" issue, and they solved it.
I have had the computer for 3 days, and the screen problem is starting again, and now the permits are perfectly fine in my computer, and nothing comes out as wrong in the diagnostics tool!!!!
I didnt even work with the computer, but now i can see my itunes list through the safari window, as grey letters....kinda 3D, popping out. Its very weird. And i cant capture it because when i take a screen capture, it all appears fine.
Left side of screen is the affected. And no, its not a condensation issue.
Also, i can see some lines when i start up the computer. On the grey screen portion of the start up.
I dont know what it can be anymore. I know this is a long post, but i had to explain all what happened to it.
Any help would be great.
Thanks

Answer 1

You might want to clean up your profile. An iMac G5 will not run Mac OS X 10.6.4!
My experience with things appearing on screen but not in a screen capture is that it is on the display itself and not involving the GPU.
I think that you have image persistence, similar to CRT burn in. It is caused by having the same image appear in the same location over long periods of time, like a Safari window always in the same location, or an iTunes window, etc. The pixels get stuck showing that image.
There are different little apps that folks have developed to get the pixels unstuck. Google LCD image persistence and you can find a number of them.
Here is one suggestion;
http://www.jscreenfix.com/
Dah•veed