Windows 7 - malware message "ON ACCESS SCAN MESSAGES"

Greetings,

I just joined this forum, and have found it incredibly helpful.

A little background. I am a tech coordinator, supporting over 100 end users. Just started in this position.

A number of users are getting malware, and the routine is a pop-up that keeps coming up, and cannot be shut down. The pop up screen has a box with various messages, but on the title bar is "ON ACCESS SCAN MESSAGES".

I have had no problem removing it with malwarebytes. My question is after much searching, where is this coming from? I would like to alert the users how they are getting infected.

Depending on the computing environment, it could be coming from the net (one particular site that gets visited each day), or from someones FD that is unaware they have a worm/virus on there.

It's possible too that the infection wasn't eradicated completely and some small fragment remains on a PC and "calls for backup" when you access the net.

I regularly have to use my FD at school and when you have several hundred people plugging in various FD's into a network, it's inevitable that one of them will have a virus or worm on them. It's not unusual for me to come home, plug my FD in & MSE detects a worm/virus on it.

The schools solution is to re-image all the PC's every night. This gives them a clean start the next morning, however by the end of the day, there's bound to be something roaming the network.