An instructor where I work has Powerpoint presentations with hyperlinks, mostly to local files like AVI or WMV videos, or occasionally PDF documents. At home and in her office, the links behave as expected: Windows opens the linked file as if someone had clicked on it from an Explorer window.

On the classroom computer, however, we first get a warning message about potentially harmful information asking for confirmation to proceed. After clicking "OK", we get:

Error:
No program is registered to open this file.

She has Office 2003 at home and it works. She has Office 2007 in her office and it works. She has Office 2007 in the classroom and it does not work. The computer is much older, so there's no telling what tiny little bit of configuration is causing this problem, but it's nothing to do with file associations or missing programs, because everything needed to run the files is installed and functioning properly. They just won't open from a link in a Powerpoint presentation.

Any ideas?

(Keep in mind that this is a classroom computer, and ditching this and/or that Microsoft product might be your knee-jerk suggestion, it isn't feasible.)