Sorry Bean, I hadn't seen this thread for a few days.
Yes, I know the LR 5 is not backward compatible it is only 7 or 8
What torqued me was I was running the beta LR5 on my Vista machine and it worked fine, so i downloaded the full program after release knowing it was for 7 or 8, but figuring it would work for the vista..........Not!!
So I'm still working with LR3 and am fine, but will eventually want to start using the LR5, so will have to upgrade eventually.