My Int Security Plus prog stopped daily scans 11 days ago. Cannot restart. Why?

What happens when you try to run a scan?  Is there any sort of message?
 
The other thing you'll want to try first is uninstalling and then doing a fresh install.

Progress window shows a slit of green and 1 sec shows as time elasped.
Last scan only lasted 33 secs and showed 3 threats removed

Our scans are typically pretty fast.  Did you get a clean scan after those three threats were removed?  
 
I'd say uninstall and reinstall, then if it still isn't giving you a good scan result, go ahead and contact our support.  They'll be able to look at your logs and see what is going on.  If you do have an infection of any kind they'll be able to help you remove it.
http://www.webroot.com/us/en/support/contact

I have the same problem on more than one computer.  Checking in I often find that Webroot has not done a scan in days and that one can not be initiated without shutting down Webroot first.  That has to be done either through the task manager or via  a reboot.

Hey @, 
 
If you haven't already, I'd suggest heading over to our Support page and talking with our incredibly friendly and knowledgeable Support team. It's the best way to get your issue worked out as fast as possible. 
 
Thanks