Did you try rebooting? If so, how about uninstalling and reinstalling?
What do you mean the entire right side of the window is grayed out? Which window?
Are you right clicking to copy, etc.? What are you copying? Did you try Ctrl C and Ctrl V? Does copy work in other places, outside of MC?
How about copy to clipboard (the cover art function)?
Just some things to investigate, so you can come back with more info.
-Chris