Lock up Problem

Tonight I just had something happen that I can't seem to fix. For some reason when I right click on the desktop I just get the hour glass and thats it. Then if I try the start menu or any of my desktop icons nothing works. The mouse (hourglass) moves but no action from it as far as clicking program icons or what ever.
When I use ctrl-alt-del it pops up but shows NO activity and nothing running.
If I reboot (the "button ") and do NOT try to right click on the desktop everything works but the second I right click on the desktop it's over!

Help!!!

Thanks
Paul