Need some general information

[damm.admin]

Hello everyone. No need to say that I am also a buyer of mp3/mp4 product on ebay lately. I would like to know what causes the players to become dead so soon? Is it the ICs they use of the firmware itself????

I mean, I have a mini clip (apple like) mp3 that is still rocking, just some of the keys are a bit loose but the size(2GB) is real and genuine and the music plays well.
From another buyer i got a mp4 (4 GB 1.8") apple nano like ( the small square type) and this player display worked well for some days and suddenly I dont know how it was dead. BUT the music was still playing and the size of the disk was genuine 4Gb (got 4 Gb of data holding with no problem).

Given my two experiences, what advice can you give me concerning buying mp3/mp4 players on ebay again? I mean There are players that do work and those that comes fake.Any precaution that i may take to safeguard my firmware ??? thanks..