If it's not a hardware issue, you could reflash the operating system without deleting your userdata partition. App settings etc. might get deleted tough.
You'll need RSD Lite
and your firmware version from here
. Extract it, and delete the line which erases the userdata
and just to avoid problems also delete any lines that contain "GetVar", "var" or "oem" Don't forget to save the changes.
Go into fastboot mode first:
Turn off or reset your phone first by pressing and holding Volume-up + Volume-down + power for a few seconds until your phone switches into “Boot Mode Selection Menu”, scroll down with Volume-down to highlight “AP Fastboot“ then press Volume-up to select it, you will get into ”AP Fastboot Flash Mode“.
then open RSD Lite, select your modified XML file and flash by clicking "Start".