ms prompt - net???

Have a home office network, peer to peer, 3 units, using NetBeui, Client for Microsoft networks and 3 Com etherlink III 3c509B Combo cards and coax. These use Win 98. Once in a while I unhook one of the units, and put a Win 95 unit in it's place [the win 95 unit works better with an old CD writer I use]. When I did it this time, I now find unit #3 won't shutdown normally as long as both the Win 95 and it are on the network. At shutdown the Win 98 unit #3 has a window pop up entitled MS Prompt - Net and says cannot close down until this program closes. Control+alt+del doesn't show the program, and after a minute or so the unit locks up requiring pulling the plug to turn it off. The other win 98 shuts down normally. Discoonect the win 95 unit before turning the #3 unit off - no problem. I've had a lot of peer to peer, Novell and Lantastic experience and never seen this one. Anyone know about it????