mdbohunter, i have the same unit. did a backtrack on it the other day, worked great, took me awhile to figure out how to get it off the screen when i was done, this is how it is done:
1. press the menu button.
2. scroll down to preferences
3. hit enter.
4. highlight clear memory.
5. hit enter.
6. you now have 5 choices.
a. all track logs
b. POI/routes
c. routes
d. reset defaults (watch this one, it will erase all the changes you made
on the unit)
e. all

hope this helps you in case you need it.