Guys im having a mp3player cum pendrive of 1gb capacity...one of my frnd took it fr sum use and after he got it back wen is insert sum data to it it gives me a error "THE DISK IS WRITEPROTECTED" . i have no idea wat to do ...even if i try to format it, it gives the the same error i hve run an antivirus chk with AVG for tat it gave me no virus detected.  I Have no idea wat to do please help me guys.........

Did you ask your friend what he did, e.g., what he loaded on it?  Might give you some idea of how to fix it.  Have you talked to him about replacing it?

This probably won't work but have you tried right-clicking on the device and clicking properties?  Then uncheck read-only.  (or looking at the advanced options)
 
Also try another computer.  I've had similar problem and it turned out that it worked "SOMETIMES" on another computer then it crapped out completely  

Do you have a HOLD button on the MP3 player which prevents buttons being pressed on it while its in your pocket.
This must be disabled when its connected to your computer to be able to write to it.

Some of these things have a small write protect switch to protect the content from accidental deletion.

 
your friend came on your pendrive...ewwe...just kidding, your friend must have "loaded"...hehe some secure software on it or enabled some built in software.  

I would see if you could right click on the drive, select properties and see if the drive is full or if there are any files on the drive that are write protected.