Impressive iMac 24" Dark Spots

Question

Sorry to repeat. But I don't understand why what I posted yesterday disappeared.
My story is long to write down. I hope any of you who got experience with dark spots/patterns on iMac screens can help me to look into the problem I appreciate your help.
The associated pictures of this post can be found here in my google album:
http://picasaweb.google.com/zhangchao/IMacDarkSpots?feat=directlink
I purchased my iMac 24 inch in July 2008. After using it for 2 months, I noticed some dark patterns started to appear on the machine’s 24 inch screen. I should have taken it to Apple back then if I wasn’t using it all the time.
These patterns become clearer if you set the background to white. A lot of iMac users have reported similar problems. Actually, if you google "iMac dark spot", you can find a lot of such posts. The patterns I got are very similar to what’s reported here in the very first picture here:
http://discussions.apple.com/thread.jspa?threadID=1915086&tstart=15
I contacted Apple two weeks ago when I finally got some time free. I was asked to go to the Apple Store here in Milwaukee’s Bayshore mall and left my machine there for 3 days for them to investigate. When I went to the store to pick up my Mac, I talked to the gentleman who did the repair and investigation work and a manager. They basically told me that I got the patterns because there was some weird “white substance” everywhere in my machine. The substance was circulated between the layers of glass cover and the LCD etc appearing to us as the dark spots. However, it’s easy to remove the stuff between the LCD and the glass cover but impossible to remove the stuff which got into the LCD.
They strongly suspect the white substance came from where I placed my machine (my living room indeed). They don’t think the “white substance” is hair or fiber. It’s like pure dust and very subtle. Since they believe the cause of the problem is environmental, they will not fix it for me under my warranty.
But I disagree and I think the white substance indeed comes from inside of the machine.
Overall, I think my apartment is pretty clean. The machine is always placed on a wooden table which I clean every week. There aren’t a lot of things around my iMac so it gets good air circulation.
My apartment is located in an apartment community. Hundreds of people live here. The community is not new (20+ years old) and is professionally maintained. I talked to the manager of the community and some of my neighbors, none of them have ever heard of anything similar.
In my apartment, I have never been able to observe the "white substance" anywhere aside from the iMac. I did some investigation into the case, placing some blue tape under the hole of the back of the iMac where air comes out. After doing that for over one week, the only place that I can observe any "white substance" is on the piece of blue tape. The pictures in the album will make everything clear. This makes it really hard for me to believe the problem is environmental. In addition to that, if the "white substance" is so subtle and so weird (as if the only purpose of its very existence is to get iMac into trouble. Other computers and electronic devices in my apartment are completely fine), how can so many people got similar dark patterns on their screens?
However, Apple doesn't take this as evidences that the problem is not environmental. Right now, I am gonna buy air purifiers and hire professional indoor air inspectors to help me to find where the trouble is.
I read several posts re "iMac dark spots" problems. Some lucky guys simply got their screens replaced by Apple and others were just left with no help.None of them actually gives detailed explanation of the cause of their problems. I notice most of reported problems happen to iMac 24 inch machines shipped in early and mid 2008.
If you have any insights, please let me know. I greatly appreciate it! Thanks!

Answer 1

Since you purchased your iMac in July of 2008, you are right on the edge of your one year limited warranty.
Go here https://selfsolve.apple.com/GetWarranty.do and see if you iMac is still within the one year limited warranty. You will need the serial number which is located... click the Apple Menu then click About This Mac. Where you see the Version number 10.5 click there twice. The serial number will be displayed there. If you can't see it there, open the System Profiler. (Applications/Utilities) Select Hardware on the left. The serial number is on the right.
If it were me, I'd take the iMac back to that Apple store and *ask to speak to a manager*. Tell them you are dissatisfied with the outcome of your first visit and want your iMac repaired.
Make sure and take in your original purchase receipt from when you purchased the iMac and any other pertinent paperwork.
*"They basically told me that I got the patterns because there was some weird “white substance” everywhere in my machine."*
I don't believe that.
This problem started within 2 months of using your iMac. It would take the force of an F1 tornado to get that much dust inside the monitor that fast.
If you still can't get that Apple store to repair your iMac, if you can, go to another Apple store OR find an Apple certified repair provider. Perhaps you know of a friend with a Mac that might be able to give you some recommendations for a place to take it. But make sure they are Apple certified.
Carolyn