are you sure its not somone messing with netsend?

do you have an antivirus software installed? (if not slap your admin)

Has the AV given you any indication what it is?

where does this pop up? is it like a webpage pop-up, or like an error message, but with that message?

do you have the messenger service disabled?

we need WAY more information at this point.

but here is a generic answer.

Update all virus Definitions,
Install something like adaware, update that
unplug from the network
restart in safemode,
scan for viruses
scan for adware.


do it on one computer that is having the problem, to start with, find the problem before trying to fix it on every other computer.

still having the problem, let us know.