remove and reinstall iTunes for MacBook Pro

I recently upgraded to Yosemite, including iTunes 12.0.1. Everything works fine. Except that the App Store doesn't seem to recognise that I have iTunes installed. I keep getting the update message to update my iTunes. I click on "Update" and it loads about 50MB before stopping and reverting to the "Upgrade" message again.

I posted my question elsewhere here and was told to remove iTunes and reinstall it from the App Store. Can someone direct me to the procedure for doing all of that -- removing iTunes from my MacBook Pro (Yosemite) and reinstalling without losing all my songs (about 5000).

Thanks in advance.

Doc