Doesnt go to navigation screen nextar x3-03
If it says it can't find map data then your SD card is corrupted.
It's a fatal flaw in the WindowCE 5.0 operating system that was used for Nextar GPS builds. Basically, if you have a power glitch while it's reading your SD card (contains the maps) then your SD card get's corrupted.
Don't expect any help from Nextar. You will have to get the original data from another person's SD card with the exact same model