While you guys were posting here, I followed the same path after reading up some instructions from the Tutorials Index. To recap, here's what I did:

1. Flashed CURE firmware into the unit, using GarminCure3 and Updater.exe.
2. Formatted the unit using RMPrepUSB.
3. Flashed ORIGINAL firmware into the unit, using GarminCure3 and Updater.exe.
4. Loaded missing operating software into the unit, using WebUpdater.
5. Reset unit to Factory Default by holding the lower right corner while booting.
6. Loaded detailed navigation map into the unit.

Unit working as new!

This forum has once again proven its absolute value. It not only has a wealth of information for those who are prepared do do some research themselves, but it also has many great and helpful members who are prepared to guide less experienced members into the right direction. Many thanks to all who have helped me and by doing so, also have helped my friend get a working GPS again! Too bad I can like posts only once. In this thread I would have wanted to click "like" at some posts many times... I'm very grateful for all the help received!