WTF!

I rebuilt my internet PC with a new MoBo, reinstalled window, etc etc last nite. All is well except Firefox. For whatever friggin' reason, my MS wireless 5 button mouse doesn't work right. I have the smaller top side button configured to "close" and the bottom side set to "back." Well, both do what they're supposed to in MY DOCUMENT folders, and when browsing the net in IE, but the damned "close" button won't work in FF!
Any advice?
Plus, I can't seem to fix the damn scrolling. Smooth scrolling is enabled, but things are still choppy and the slightest touch of the wheel moves about 5 lines. And it keeps scrolling well after I stop rolling the wheel. I never had any of these problems before. And yes, I uninstalled the mouse and reinstalled it, although I haven't tried doing that with FF.