|if you are really worried about it spreading, you could ask your administrator for assistance?|
other steps would be to disconnect your connection to the work group?
I would try checking your proxy server under internet options, or your host file. these are easy things to check. or try to start your browser by right clicking and start without addons and see if it redirects.(if it doesnt, its something you added as an add on)
I would try malwarebytes, trojan remover, or hitmanpro. see if something in there hits on something.