i have spoke with samsung support about a few problems with stuff not working or freezing up. 99% of the time this can solve many software issues.
Power down device
Pull battery, wait 20 seconds
Insert Battery
Enter Recovery Mod by Holding POWER, VOLUME UP, & HOME BUTTON TOGETHER
Wait for vibrate and screen to appear and release power button, then release all buttons when recovery screens opens
scroll down with volume keys to "WIPE CACHE PARTITION" select using power button
when finished select REBOOT SYSTEM NOW