Since you are not part of a Domain, and i am assuming that everyone is part of the same workgroup, every user has to have an account on each computer they want to connect to.
So the way you have it setup right now, is the way it works. Just create a generic account for everyone to use (like you have done), and just have the other users map your shared drive. Although it has been a while since i used this method, i believe that once they map your share folder with a user name and password, the wont have to again (unless the password for the generic account changes).
So, try having the other users map your shared folder.