Umm... As a guess I'd say that maybe the user changed some of the windows display settings. You can change the dots per inch (DPI) and all sorts of things like font sizes and colors, etc. The tas 7 setup program is probably not coded to be very tolerant of people changing all kinds of setings. Two things you might try in windows: (Hopefully you use XP)
Right click on the desktop and select properties.
Go to the Appearance tab and select the Advanced button
Use the drop down list to select the various Items
The font sizes for things which have a font size should probably be 18
Or
Right click the desktop and select properties
Go to the Settings Tab and click the Advanced button
Under the general tab there is a selection for DPI.
This should be set for 96DPI. If it is not set it that way.
If neither of those fix it then you might try thumb screws and a waterboard to "help" your power user to remember what they did.