I have an rca 27v513t and there is only a lower portion of picture but full sound.

check thet rca video is on the video port and rca sound on the sound port alternatively choose screen mode with remote

To reset it to its factory settings, you must have its original remote control. A universal remote won't go.

try to replace the lamp..

Maybe the eeprom are corrupted and need to be changed

unplug it from the outlet,wait 2 min. then plug back in to see if it reset. if not suspect it to be in the power circuit of unit

Well if you still have sound it means that not everything is dead inside. You could take off the back cover and look for cracks or broken solder joints(specially around the larger transformers on the main circuit board, You might also want to look at the small board mounted on the back(neck)of the picture tube and make sure it is plugged in all the way.
As for resurrection you may need patience and lot of solder. Good luck

if you have your tv connected to your pc with a vga cable, you will not get sound, since the vga does not carry sounds, only pictures. to change the settings on your pc to make full you will have to change your resolution size on your pc in your control panel

go to menu of your remote and unlock the fpa

Here is something that I found that might help?

http://www.netnoise.com/boycott_rca/rcabook2007-8.html

If the TV is in "parental lock", then it will not respond to the buttons on the front of the TV. Get a cheap universal remote control, program it for RCA, turn the set on and go through the menu to unlock.