No A/C due to Navigation screen not working

I changed the battery in the car so I knew I would have to enter the radio and navigation system codes to get them to turn on and work. I put the radio code in and it worked as it should. The navigation touch screen would not come on for me to be able to enter in the code, it was just a black screen that appeared to be off completely. I pressed all the side buttons, the 'menu' and 'a/c-info' buttons, nothing would work. After a few weeks the 'Enter Code' would pop up on the navigation screen when I started the car. I tapped the screen but nothing would happen. The touch function of the screen would not allow me to put in the reset code. This happened every time the screen would turn on but not every time I started the car. 1 out of 30 times the navigation screen would come on and the other 29x the screen stayed black. Eventually, when it popped up, I got the navigation touch screen to accept the reset code and it fully turned on. It stopped asking me to key in the reset code but the navigation screen still only comes on 1 out of 30 times I start the car. Having navigation in the car is not exactly the only problem. I need the navigation screen to work because that seems to be the only way to access turning on the air conditioning for the car. Do you think this something is loose or does it seem like the whole navigation computer needs replacing? I would just like the A/C to work. Any info helps, if you have some clues please let me know.