You don't need to delete anything at this point. If you download WMP 10 and re-install it, it will most likely fix any problems from the old install. In other words, it will install itself over the old version.
For you software for the CDROM: find all the CD's/disks/whatever that came with your compter when you bought it. One of these CD's/disks/whatevers will say that it is for your CDROM. If you put that CD into the drive, you should be able to re-install all the drivers and what not.
So . . . in summary. Download and re-install WMP 10. If that doesn't work, find the disks/CDs/whatevers for your CDROM and re-install those. At this point, there will be no deleting of anything. If both those suggestions don't work, let us know and we will suggest something else.
I always save deleting of a program or hardware device as a last resort. I found that out the hard way once.