Let me preface by stating that I feel sort of lame for having to ask questions about operating Windows XP, but, here goes...

I have an administrator account on the machine (XP Pro SP1, btw) and just created a new account for someone else in the plain old Users group. I have two irksome things I need to change, but can't seem to.
1) In my account the app associated with the "mp3" extension is Windows Media Player as it should be. In the new user's account the associated app is MusicMedia Jukebox (or whatever it's called) as it was when I originally bought the computer. In the user's account I cannot modify anything in the "file types" box (all buttons are greyed), so any time an mp3 is double-clicked a message just yells that it can't find jukebox any place (because I uninstalled it eons ago).
2) For some reason, after creating the new account all the icons of Microsoft Office documents change to one of the plain old default icons on both of the accounts and there doesn't appear to be a way in XP (as there is in prior OS's) to select an icon for a given extension.

Any enlightenment will be very greatly appreciated. Please don't be greedy and share your two cents. Thanks.