Monitor Problem - Sun GDM-5410

Hi,

I have a 21" Sun GDM-5410 monitor that has been working like a champ for the past 3 years. Yesterday something strange, and perhaps bad, happened. The following is a description of the symptoms:

1. The screen is quite blurred, especially when reading text (of icons, taskbar, etc.). No correction via "Convergence" adjustment fixes it.
2. The screen seems to correct itself and regain clear (much better) focus when the predominant color on the screen is white.
3. Any other predominant color (black, brown, green, blue, etc.) would render the screen blurry again.
4. The same symptoms are experienced in any other combination of resolution/refresh rate.
5. The screen would momentarily pulsate by expanding and contracting if switching from predominantly non-white to predominantly white screen, but will not do so if switching from pred. white to pred. non-white.

I've done the following to troubleshoot (in that order):

1. Degaussed the monitor several times - no go
2. Adjusted "Convergence" - no go.
3. Reinstalled Video card driver (ATI AIW 9600) - no go.

I have not done any changes to the PC, and or the environment relevant to the PC and/or Monitor. I am running Windows XP, and it is set to not update itself automatically. I am running Symantec Corporate AV which is up-to-date. The video card drivers are up-to-date.

Any suggestions about the potential cause of the problem will be greatly appreciated!

Thanks!