I have several computers that are being used by unauthorized people from who knows where. None of the AV products finds them. But within an hour or two of me connecting a new machine to the network, NetFX has been installed, Windows Media Player has been setup to allow remote access, new user names have been created, and several hidden network adapters have been created (and no, I don't mean the hidden ones that are normally setup with Windows 7). I've tried turning off every service I can think of that might be a problem, setting up a local security policy (oh yeah, and MANY group policy entries added ... not by me), I don't know what else to do. If I fire up WireShark, sometimes I will see some of my files being sent ... somewhere. It has to stop. Can someone please help me lock down these machines?
There are 9 computers, all running Windows 7 ... except the tablet which is running Windows 8.