Even though my charge is full my player will play for a little while then go off. i can not get it to come back on for days afterwards then it will just suddenly pop on. my husband got it for me as a gift and it breaks my heart to think that something has happened to it. when i plug it into the computer when it does this it will come on and play, it will not say connected and as soon as i unplug it, it will go back off.

SOURCE: Computer Won't Recognize My MP3 player

Try reinstalling the drivers for your mp3 player. Or maybe updating them here is a link to recent drivers to your player http://esupport.sony.com/US/perl/swu-list.pl?mdl=NWE107&UpdateType=Updates

Network Walkman

esupport.sony.com

Sony eSupport Model Support

SOURCE: Wont Charge

Yeah, I had this problem too because I was connecting the USB proprietory connector/cable at the front USB drives on the computer. If you have been using front USB connecters, try using the back USB drive connecters.

It worked for me :)

SOURCE: Battery won't charge.

I just figured out the problem I had just like yours. I have three different sony MP3's and thought all the usb cables were the same. Well after changing out the usb cable my 438f started charging. I was using the cable from my s615f and the same is true if I use the 438 cable on the 615-full battery instantly. Also sony does not replace these batteries. If in warranty from purchase date, they will exchange with "like product" for $29, or repair yours for $77. Both prices include return shipping. http//eservice.sony.com

SOURCE: I have a sony NWZ-E435F mp3 player

go to run commend and type
cmd\ then press enter
format ......
drive name which u want format then press enter

SOURCE: I have a sony walkman a726 4gb mp3 player that

I got a usb wall charger and it revived it