Windows media player corrupted by virus

Hi! One of my favourite computer programs is Windows media player which Myself & my wife use frequently. Recently my system crashed due to a virus. I used safe mode to restore my system to a previous date, but after that Windows media player was corrupted.

As a windows component I cannot uninstall this program to reinstall it? It gives me the error message "the file wmp.dll has a version number of 9.0.0.2980 where 9.0.0.3075 was expected. The windows media player is not properly installed and must be reinstalled. Do you want to install the player from the microsoft web site?" I go to the microsoft website which will not allow me to re-download the file- as it is already installed.

I then tried reinstalling my Windows xp components from my startup disk that came with my Dell computer, but this was also to no avail. 

Please help! I don't know how to proceed & I would hate to lose the use of this program forever.