I just installed iTunes 5 on my two *books and PC. Things went smoothly (of course) on the *books, but Windows is having lots of problems. It doesn't seem to look for computers sharing music, and it doesn't share its music, on the network. I went in to preferences and all the things that enable sharing are already checked. After clicking OK, iTunes crashes. Is there a copy of iTunes 4.9 I can download to roll back to?