Sorry to not answer your question. Does control-alt-delete not bring up a window where you can log off?
First, don't panic. If it comes down to it, you can probably rely on somebody at the competion to have an image you can put on. (first support, other teams, etc), but I'm sure you want to take care of it yourself if possible. I would download and install the image again. Just use the basic driver station version without labview or windriver.
The procedure:
http://wpilib.screenstepslive.com/s/3120/m/8559/l/92211-imaging-your-classmate-veteran-rookie-image-download
The
files
Brian