What this error is trying to tell you is that your laptop already has
a connection to your PC using a different set of username/password
credentials than you are trying to use currently to connect.
When you see this error, on your laptop right-click on "My Network
Places" and select "Disconnect Network Drive". Search the list that
comes up and disconnect all other pre-existing connections that show
between your laptop and your PC, and then after that, try to connect.
HTH,
John