Same problem with my New Dell U2410. The colors were WAY, WAY off. I'd open the same photo with quicktime viewer, and windows photo viewer and the colors were Terrible in Windows photo viewer, Yellowish Green Tint.. and colors were dark and not Vibrant.. I have a 24" IPS Panel, wide gamut amazing color display with the most vivid pictures I've ever seen.. but not in Windows Photo Viewer.
I just went back to the sRGB profile and wow did it make a difference. I now have great colors.
thanks for the easy fix. Another problem solved by SF.