I have a computer running Windows 7 that shares some files on the network. This works fine for a while until for some unknown reason the computer decides that it is connected to a new, unknown public network and disables the file sharing capabilites.

Nothing physically changes with the computer, it is still connected to the same network via ethernet cable. But it does misidentify the network every other day, just plugging out the ethernet cable and putting it back in leads Windows to correctly identify the work network and enabling the share again.

Is there some way to stop Windows from trying to identify the network automatically, and just tell it that the network on that computer will never change?