Reinstalling office will not solve any password problem.
If you don't mind I would like to ask couple of questions to find out about your situation.
Are you connecting to a LAN mail server or to your ISP's POP server ?
If you have mail server in LAN then you can change the password on server side, that's the work around.......and if you POP server from your ISP then just give them a call, they will reset your password.
Cheers