Windows 7 works fine for me. I own Vista Ultimate edition (Microsoft gave it to me for free... I was a beta tester) and I prefer windows 7 to vista. No problems at all on my end.
I had this problem as well. I performed an upgrade from windows vista 64bit. I then decided to format the system and do a clean install, now I have no problems and the operating system is as stable as Vista SP2... just faster.