Exhibit 4g SGH-T759 Screen Stops Responding

Hello guys, sorry if I am posting in the wrong area but this is my first post. I have an Exhibit 4G SGH-T759 on T-Mobile not the Exhibit II. My phone works good touch and all but sometimes for no apparent reason the touch screen will stop responding or when I touch a certain part of the screen it will select things that I did not intend to select. Sometimes I can fix it by pressing the capacitive back button and other times I will have to shut down and reboot. It's almost as if it is not calibrated but when it is working it works good. Also, when I press the power button and I get to the Sweep glass to unlock screen, I will swipe the screen but the screen will not go off the screen but will shift over a bit and kind of vibrate and sit there until I keep keep swiping or press the back button or I might just have to reboot the phone.

I have tried going into "Settings" "Display" "Horizontal Calibration" calibrated the phone but this has not solved the problem.
I am running Android 2.3.3 which is as far as I know the latest version on this phone. I have tried wipe data/factory reset and wipe cache partition several times but this hasn't fixed the problem either.

Any ideas as to what I can do to fix this?

Thanks.