My daughter had about 50 single player worlds on XP and now has a Windows 8 laptop. It wasn't until I read how to access her 'saves' with your simple instructions, I was able to transfer all her worlds to the Window 8.
The only problem now is none of her multi-player server addresses work since the 1.7.2. update. Is there a way to fix this or, failing that, a list of servers which will work in the new version?