I have bought a 4GBipod nano clone and having the same problems with file corruption, player restarting etc. I have decided to get a refund. Luckily I got a 6 month warranty from the retailer.
To delete the corrupted files, I found this on wikipedia :
Problem Deleting Corrupted Files
If a player has a corrupted file and one is not able to delete that file then please see the following steps:
1:run cmd in run dialog box.
2:type chkdsk /r drive name
3:it will ask whether to covert lost chains into files,type y (yes).now it will scan your player
4:goto folder option in control panel.enable show hidden & system file and click on show operating system file too.
5
elete file or folder named "Foundxx" from your player.
Now your corrupted file are deleted
IT WORKED for me!! I hope it works for you too