Windows 7 color scheme/theme problem.

Everything is fine while I work on the PC. When I leave it be like that for aabout 10min. (when display turns off), Windows automatically changes theme to Windows 7 Basic. It’s really annoying. Any way to “fix” this?
I am not using any other special themes that would cause this problem… Just classic Win7 Aero with a color change and another desktop picture and it keeps reverting to Basic…
Answer #1
A quick Google search..
http://answers.microsoft.com/en-us/windows/forum/windows_7-pictures/windows-7-automatically-switching-to-basic-non/7f4917ff-135d-40e4-866b-ac760642763f?page=3
There are also loads of posts of this happening with ATI video cards.
Answer #2
Aero Peek was already checked…but anyway, I will wait and see if the problem still persists.
Answer #3
"The color scheme has been changed to Windows 7 Basic
The current color scheme has exceeded its allowed memory so the color scheme has been automatically changed to improve performance. Click to see more information."
That’s what it says…When I run troubleshooter it ‘fixes’ it – changes back to my aero theme but only temporarily. In Troubleshooter it mentions that Desktop Windows Manager is disabled… I’ve searched everywhere how to fix this and nothing…

-Google image, but that’s the thing…