XP user can’t run progs created by Admin

I have two admin accounts and two user accounts on an XP-Pro machine. I have installed various pieces of software, including Office 2000, as admin. After installing the software, any user with less than administration rights cannot run the software. As soon as a user logs on, a message shows on the screen that “Office must be re-installed from its original location”. Although Office CAN be run, Microsoft FrontPage will not run at all.

If I give that user administration rights, the software works fine. If I assign Power User or less rights, the software will not operate or gives the described errors. Other pieces of software perform similarly.

How do I create a software installation that can be used by ALL users on the machine, regardless of group?