OS X :: Keyboard Shortcuts Stopped Working / Unable To Cut Paste From Mail Message

Everthing's been fine since I first setup my Mac Mini over a year ago....2 or 3 days ago I noticed when I tried to do a cut/paste from a mail message to a field (using Cmd-C Cmd-V) in a web page, it didn't work. It's alsways worked before but I chalked it up to the web form not taking "pasted" input. But then I tried from a text document to an email...same story. I highlight text with the mouse, do Cmd-C and get a "bong" sound, then go to where I want to paste, do a Cmd-V and nothing gets pasted. I take it the "bong" means some sort of error or invalid input occured?

I restarted the Mini and it worked for a while (at least when I tried it right after logging in). Then yesterday I had to restart my Mini again and the shortcuts aren't working again. If I highlight text and then right-click the mouse and select copy, then move to where I want to paste and right-click and select paste it works fine....just the keyboard shortcuts don't work. I checked the sytem prefs, keyboard pane and saw nothing out of the ordinary.....any ideas out there?