Lost CTRL and ALT keys
 

I've spent a day on this, and it's time to ask for help.

My CTRL and ALT keys have stopped working. CTRL-c give you a 'c'.

This is new. and it happened when around the time that I was trying to set screen capture and window screen capture to different keys.
(It could also have something to do with that around this time, I switched to KDE from Gnome, and back to Gnome.
(Those are the only two things that I can think of that could have had an effect.)

I'm running Centos 5.8 fully updated.
It's a Microsoft Wireless Comfort Keyboard 4000

I have basically the exact same machine next door. The CTRL and ALT keys work fine on this computer.
I've been comparing these two machines
/etc/sysconfig/keyboard is the same
/lib/kdb/keymaps/i386 are the same
/etc/X11/xorg.conf are the same, for the keyboards

I ran dumpkeys and the output files are the same on both machines.

On the 'bad' machine, Keyboard Shortcuts shows "Take a screenshot of a window" is set to Alt_R (I can't change it because pressing the Alt or CTRL keys does nothing) The Alt_R key does work.

Using gconf-editor - apps - metacity - global_keybindings
shows both computers have 'run_command_window_screenshot' set to <Alt>Print.

Where should I look next? I'm lost

In the console (out of your DE) does Ctrl+C work as it should?

This might give away my level of expertise, but What's a DE?

For further info. To resolve this, I am sitting on the computer
where CTRL and ALT works, and I have FreeNX's onto the machine
where they don't. I'm using two screens so I have two xterms up.
One local, one on the other machine.
In the local Xterm CTRL and ALT work. In the remote Xterm they
don't.
I have found that by running #stty -a on both there are
slight differences.
GOOD rows 32 Columns 143 -ignpar ixany
BAD rows 39 Columns 128 ignpar -ixany

Solution
It turns out that it's a known FreenNX bug.
If you turn on the flag which lets you hit crtl and the location of the cursor is evident, then crtl doesn't get passed to the remote machine

http://www.nomachine.com/tr/view.php?id=TR03G02202