I installed Windows 7 a couple of months ago, and since then I'd been having some weird oversaturation issues on both of my screens. Oranges, reds and some greens seemed to be almost retina meltingly oversaturated. I'm not a big fan of fiddling with my monitor controls - as I have a Spyder calibration thingie. I tried calibrating several times and still had very saturated colours.
Images created on my laptop or work PC at lunchtimes seemed fine until I opened them up on the main PC at home. Last night I finally snapped after recalibrating and messing about with colour profiles. A frenzied bout of surfing finally turned up the cause and solution to the issue. If you are using an Nvidia video card, Windows 7 and up to date drivers - and you think your colours are way too dayglo, then open up the Nvidia controls, click on 'adjust desktop color settings' (in display), go down to the bottom and change the 'Digital Vibrance' setting from 90% (what were they thinking?) to 50%. The digital vibrance thing was kicking in despite having 'other applications control colour settings' check and not 'Use Nvidia settings'.
I'm happy now Stuff created pre Windows 7 now looks like it did before... the only issue is that some recent stuff looks a bit washed out (as they were painted taking into account the high saturation)