Since the operating system and navigation software are preloaded into the internal flash memory of the GPS, the freezing may either be software or hardware failure. First, press the "Reset" button or push the stylus into the "Reset" hole, to see if the navigation software can load successfully. If the program still does not load, then the software may be corrupted. Also, if the internal memory fails to read or write and the software cannot load properly, it may be caused by hardware failure. In this case you must return the unit for exchange or repair to the retail location from which you purchased it, or contact Nextar for further assistance.
For technical support for your Nextar GPS see http://www.nextar.com/frontend/support.asp
or you can phone them on 888-849-0846