How can I fix my WMP 10?

I have a problem with my Windows Media Player 10. I downloaded the version of Windows Media Player 11. I didn't care for it, so I removed it from my computer by going into Add and Remove programs. I went back to Windows Media Player 10. But now I get this message everytime I want to play a song from My Music collection on my computer, or when I try to rip or burn music...

C00D11CD: Unknown error

Windows Media Player encountered an unknown error. This can occur when another program or operating system component encounters a problem but does not communicate the nature of the problem to Windows Media Player.
Error ID = 0xC00D11CD, Condition ID = 0x00000000

I can still play music off cd's but not from My Music collection. I am so frustrated about this. Can anyone there please help me with this problem...I do not know what happened here. If I knew this was going to happen I would have not downloaded Windows Media Player 11, then go back to Windows Media Player 10.



Thank you for your help.

Michael