I have a tower that I upgraded from Vist 64 home premium 64 bit to win 7 64 bit home premium.
I have a dell laptop that I did the same thing to. Then I upgraded both to win 7 pro. I installed iTunes on both and the error message read that I wasn't authorized to access the library. I called apple and they told me to set up a separate user account with full administrator privileges. I did that and it worked if I logged on to the new account.
The funny thing is i have another tower that I installed pro on as a clean a clean install and everything works as it is supposed to.
I have another laptop with factory installed pro and everything works as it is sup[posed to. no problems there.
However on the first tower and the first laptop system restore doesn't work and on the first tower IE8 doesn't work at all.
I think that when I upgraded the laptop and tower there was a glitch in my admin privileges. Also after 2 or 3 months the activation file became corrupt and it wouldn't take my product keys and I called Microsoft and the only solution they could come up with was to reload. B ut they left my vista recover partition. Useless and I guess they were in a hurry.
Now I know rthat the solution would be to reload the os in both and wipe out the recovery partition. I'm hoping for some other fix. I'm a Photographer and digital artist and I'm not ready to do that. I'd rather live with the bugs right n ow.