network drive asking for password

I just got my first Vista box and now when I try to map my network drive it
is asking for a username and password. I understand this is a known issue
but I have tried changing the registry hotkeys per several suggestions but to
no avail. The XP machines log in with no user, just a password. The Vista
box is filling in the computer name. We don't have a domain just a small
little home network. I am not familiar with Vista so I am a noob.

Thanks for any help, I can't get to my finacial info and am in a mess!