Application colors change on reboot or logging off and back in.

I am having an issue with colors in my applications changing. Every time I log off and back on or reboot certain parts of application windows have changed colors.

For example, the background of the Firefox Bookmarks sidebar. Sometimes the background is light grayish and other times it has a more green hue to it.

It's not random either. I can make it happen time after time by logging out and back in or rebooting. I have done screen captures in both instances yet when I review the captures side by side the colors look the same.

So, I am trying to figure out what the issue is. I suspect that if the screen caps look the same that the issue has nothing to do with Windows themes etc...more likely a hardware issue.

BTW. My video card is an ATI Radeon 5700 HD (I have tried several driver version thinking it could simply be a driver issues).

Any input would be appreciated.

No ideas at all?