[Moved to CS4 and Earlier forum.]
Until I upgraded to CS5 I was using CS3 with Win7 and no problems
I don't know about Win8, but if you DO have problems and you have Win7 64bit PRO read...
Win7 Virtual XP http://www.microsoft.com/windows/virtual-pc/
More on Virtual XP http://blogs.zdnet.com/microsoft/?p=5607&tag=col1;post-5607
This is only ONE example of using Virtual XP http://forums.adobe.com/thread/702693