Vista - Login Name Issue

I am trying to login to a network drive that is password protected, I can
access it through http but cannot access through explorer, when asked for
login name and password vista adds the computer name to the login name and
then says login unsuccessful make sure name and password corect, I cannot
access my files and when I add a network password to my user account it does
not save. Any help would be appriciated.

Thank you
Henry