Droid X and VZ Navigator problems

I've had a similar problem, in that having my VZ Nav for over two years and loved it. Now, it has a big glitch:   For the past 3 months it starts to Nav, then it says " no gps."  Then I'm stuck and literally lost. Twice in the dark. My rep todld me to reset the phone and we did. It didn't solve the problem. The phone also shows my actual location 6 blocks to the east or two miles to the west.  It shouldnt matter, but i recalibrated the compass. I want my VZ Nav, I don't want the other free apps. I have my reasons.  It seems that the gps is not communicating with my phone. My next upgrade is in April and I don't have insurance on my Droid X. Thanks for your help!!!