GM Navigation is frozen upon startup...HELP!
 

I have an 08 Silverado and I am having problems with my navigation unit. I installed my GM nav myself in my 08 Silverado and its worked great for about a month or so until recently. A few days ago I turned my truck on and it boots up fine, but it goes straight into "Off" mode, blue screen with clock in middle, and freezes there. None of the buttons work. I pulled the fuse for a few minutes and put it back in and that worked so I was happy. A few days after that it happened again so I pulled the fuse once again, let it sit, then put it back in and it turned on frozen again. I hit the eject button to eject my mp3 cd and it spit the cd out and the unit turned on and worked great. This morning once again it turns on frozen. I pull the fuse and nothing happens, try to eject the cd and nothing happens, pulled the fuse again and left it out for my 1hr commute to work and still nothing. I am now at a loss. Any suggestions are greatly appreciated!