LG P700 User Manual page 290

Troubleshooting
Message
The screen
does not turn
on when I
receive a call.
No sound
Hang up or
freeze
132
Possible causes
Proximity sensor problem
Vibration mode
Intermittent software problem
Possible corrective measures
If you use any protection tape or case, check
to see if it has covered the area around the
proximity sensor. Make sure that the area
around the proximity sensor is clean.
Check the settings status of the sound menu to
make sure you are not in vibrate or silent mode.
Remove the battery, insert it again and switch
on the phone.
Try to perform a software update via the
website.