I had to boot each of our computers in safe mode with networking (Win7 | 64bit). I couldn't move around to do anything when they were booted-up normally.
Once in safe mode, I removed MBytes Service from the task manager, waited a few seconds for the MB icon to reappear in the system tray and then updated the definitions.
To be sure that the definitions updated, I did two things:
I right-clicked on the MB icon in the system tray and selected, "Check for Updates".
Next, I opened MB.. left-clicked on "Scan", choose "Hyper Scan" and clicked-on the Start Scan button (first thing it does is check for updates).
Afterwards, I restarted all 3 of our computers and they were now back-to-normal.