random muting whial playing and listening to music

[gcusea]

ok so i traded my slim psp because i didn't wanna buy a pandora battery to downgrade for 3.95. I traded it for a fat and it was working awsome i could play games on it listen to music. Now three days after i traded it the music starts going out and when i try turning up the volume it doesn't go up when i press down on d-pad the volume goes up when i press mute it takes a picture and when i press volume down it unmutes then mutes about 17 times and my picture box is filled with gameplay pic's from the avc player on my psp, my psp is a 3.03 oe-b custum firmware, it used to have psx and final fantasy on it but the last owner had a crapy memmory card 525mb and the game took up like 300mb so he got ride of everything.

I think the problem is ither the firmware or avc player-my avls will flicker on and off as well.

if you know why its doing this, or any idea what might be going on please share