One must login into Windows (I presume your are running some version of Windows?) or the Client for Microsoft Networks to network on a Microsoft network. Once logged into a peer-to-peer workgroup, one does not have to specify a password to access a shared resource unless it is password-protected by the owner of that resource. Open the Windows Explorer, right-click the shared drive, etc. in question, Properties, Sharing and see if you have password access implemented.
I would suggest talking to the person in charge of your network. He or she may have a quick answer to your problem. Whereas I would have to know much more about your network to answer it. Larry