Just stop playing

Alternator voltage may be to hight that make the battery to dry out,or maximum output amp not ok and battery cant be fully charge

you posted 3 times ad ANON
why>? why post 3 times, why not wait for answers.
its free here we dont get paid to help here. not one thin dime.
here I answer again
no OS stated
no media stated, fail.

tell the helper now what you are playing?
where is it, we can not ever guess media sources.
vast possible, i can name 100's

DISKS
FILES local. or even on your own server on a sub net.
or ONLINE , makes 3, and 10000000 others on each.

no operating system even stated.
Xp/vista/w7/w9/w10/ linux ,what.... must we guess?

is your internet connection working? it must or PNP will be near brain DEAD ,do that first.
ok guess w10.
why not see if OTHER USB works first
barrow a real mouse not that battery dead wireless wonder mouse?
get a real mouse
make sure that works
then put in a new battery in your wireless mouse
RTM it tells you how
USB tests, all so obvious.
use real desktop key board , that work
or USB memory stick , add file to it, see other files you have there>?

only clues here is USB dead, 2 months old.(means new? or new to you?)

next,
in w10
go to CP
then go to device manager
be ONLINE
see yell or red error there that driver stack?
bingo bad driver
reload any that are bad.

end story
google how to reload a windows 10 driver, be like 10,000,0000 hits.

Unfortunately you must buy a new one if it won't work even without the AR (action replay). If you're attempting to use it and it's not working, try using one code at a time. It might be the code itself that is corrupted.

Hello,

The MP300 uses one not rechargeable AAA battery, that will not be charged when connecting to the USB port of a computer.

When the player has abnormal behaviour, RESET the player as next:
1. Disconnect your player if it is connected to a
computer.
2. Remove the battery from the player. Wait 10
seconds, and then replace the battery.
3. Power ON the player, push the play/pauze/stop button >|| .
note
Check the correct polarity + and - of the battery matching the player.
Try a new battery when the RESET won't work.

To switch ON the player, press the play/pauze/stop button >|| .
For switching OFF, press the >|| button for at least 3 seconds.

There's a manual for the MP300 on this site:
http://www.cobyusa.com/files/manuals/MP300_MN.pdf : pdf files can be read with Adobe Reader.

I Have the same problem, but mine has vertical lines running on the display, try contacting sony support

grinding sound
that is bad thing, means IM BAD replace me.
loud and clear.
can it read , real CDs that be first, it must read first.
or its useless.
try any real install disk can you see the files, in local file program manager
no OS stated, so can tell accurate names .

hi,

Try VLC Player for your .vob files instead of just opening is.
Install VLC Player and and from VLC players file menu try to open the file.. It will work perfectly.

Regards

my name is Vidya Nagaraj. i have a SA3025 2gb gogear. I have not used for few months approx. 4-5 months. it is not switching on now i am unable to charge it also if i try charging it as usual. feeling very bad that such a nice and cute MP4 is not working. PLeeeease help solve my problem. thanks vidya

Here's the deal with WMA files - once your subscription expires (or really,  the license on the WMA file expires) - you will have to renew your music service subscription or the song will no longer play on your device. 
Use Mp3 format songs - they'll never give you this problem.