How to overcome this problem

sir/madam i wanda whats happen to my mp4 because i was having 4 music folder in my mp4 but the time comes when i just wanna add up some more music folders,it cant play.u may see the folders are in there when i connect to the computer via USB and when i remove from computer i see nothing.I try to scan to see wether it might be load with virus but no virus detected. also its sometimes show that there is ormat error while all the incoming files are in MP3 form. Please i really need your help for this disaster of my loving SONY MP4 DIGITAL PLAYER. finware version HX 8860 CM 60022.I hop you will kindly consider my request.

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