is your unit JB?

if i were to make a guess, (assuming that you have not dropped your iphone or had an impact on it prior to this), i would think that the JB app modifications could have messed up the main frame.


to eliminate this possibility, simply do a complete a restore without using the backup and set up as a new phone.

davidgary73 is right in a way that 99.9% of my first gen iphone malfunctions were caused by 3rd party apps gathered from installer or cydia.