Whats wrong with just using the second user to do all your stuff? If you are going to reformat anyway not a huge point in going to a bit of effort to fix a problem. If you mean that neither of the users can see the files then you might have to check the privaledges on the two users, if you aren't already you need to get the admin login/password and try again.

Failing that, you could always try throwing the drive into another machine which should let you read it fine then sort it out ready for a format.