i have seen this before on other networks. including my own. on the network i run we have been getting visits from what we like to call drones. they been going around advertising a url that seems to go to an error page but in reality its a trojan. without u knowing it u install a virus. this virus installs into a hidden folder and will run itself everytime u log online. NONE of the antivirus software out there have a definition for this trojan yet. i have tried them all... clean, avg, norton, mcaffee yadda yadda yadda. so in short dont click on any urls unless u know exactly what it goes to.