Hi, I would assume that the Operating System of your computer is a Windows Xp.
Here's what you need yo do;
1. Go to add or Remove program under Control Pannel
2. Delete/Remove the following;
Zune Software
Microsoft User Mode Driver Framework
Windows Media Player(it will be rolled back to previous version)
Windows Media Format 11 Runtime(it will be rolled back to previous version)
3. Go to C:\Program Files and make sure that there's no Zune folder existing, delete it if necessary.
4. Go to http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=1d224714-e238-4e45-8668-5166114010ca and download Windows Media Player 11 / Install it.
5. Download and Reinstall the Zune software
Issue should be resolved :-)