The fading to black is usually an indication of low power..

Have the battery load tested...my unit did this exact thing this spring...screen got so dark I had to cup my hands around it to even see that the unit was on...my battery would not hold a load...even tho the on-board charger said it was ready to go...

These units are very picky about current and amperage ...

I'm not understanding the data questions...

Are you saying they were in the internal memory and they are no longer there at all...??

Go under the Nav tab and cursor down to tracks or waypoints...

Then cursor right to open the menu...the track or waypoint menu will open if there is data in there...

If there is no data in there ...I think you should get a popup saying "No Tracks" or "No Waypoint"...(if the data memory is empty)...

Rickie