I came across this software and actually purchased a site license ($280). 
 I have used the free Vcon in the past, but it doesn't have the ability to
lock the remote computers.

Network lookout, is really small, has the ability to watch, remote, and
send messages to lab computers,  You can also project your screen to the
lab.   I know that there was some discussion about the vision (i think
that is the big named one) software, but It was out of the price range for
at least me.

http://www.networklookout.com/index.html


Bjorn Behrendt
Proctor School District
Tech Director
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