Yes, proxies have something about.
I have a proxy filter. When it shutdowns improperly the local addresses could be redirected to the proxy filter and nothing works: not the mouse (right click) nor the Windows Explorer folders.
Hardware problems (like external USB drivers could be related too).

Look, I’m not saying this is the problem, but, please, don’t write that my guess has nothing related to that as I have the same synthoms when the proxy filter has problems. I’m just tring to help… I know that a virus could do this and worst things… :cry: