I'm not pretty sure this is the main main cause of restarting, but it's something that has to be tried! ;D
The restart issue is probably caused by static. To minimize/solve the restarting, you should completely isolate your player from the exterior.
This is a hard thing to do, because the case has a metallic part which keeps the USB plug and the microphone in contact with the exterior and thereby allows static electricity to "enter" the device and zap it.
You have to open up the player and isolate the parts.
To isolate those parts, you can use ordinary sticky tape, or any insulator think material.
You should isolate the boards, the screws, the USB plug, the microphone, and the metallic part that touches it.
To check if it worked, you can put your player near a charged monitor/TV and see if it zaps. You can check if you isolation is good by using a multimeter.
At first, this works for MP3 players, never tried on MP4 players.. =P
Regards, and I hope this is useful!
SOLVING RESTART PROBLEM ;D
