I've been plagued with those danggonned "!" marks in my music every since I downloaded MS Media player 11.

No help from MS with out paying them.

I eventually found the source for the lost music with the Search feature and replaced the music with a click.

That went on for a year or so. What a PITA.

Just recently I was cleaning out some software and discovered I could Add/Delete MP 11 and did so.
Suddenly, I noticed the "!" marks were gone!
It had something to do with MP 11.
The arrogant MS told me it was something in my PC and they were right. It was their Media player release 11!