Question : Password requests for user with no password for share.

I have several clients running Windows XP, they are all networked but are not on my domain.  

I have shared a folder on the machines that I need to access periodically, on some machines with (seemingly) the same settings I have no problem.  i.e if I go to \\machinename\share it lets me in with no prompts.

However, on three of the machines I am asked for a username & password to get to the share, the username is already entered as \machinename\guest but there is no password for this user, I deleted the guest account and it changed to \machinename\user, again there is no password for this user.

If I turn off simple file sharing, I get the same prompt but without the username filled in.

Why is this and how do I reslove it?

Thanks

Chris

Answer : Password requests for user with no password for share.

Why I stated that. I have a home network, and i shared out my files and printers for my other XP laptop to use off of my XP desktop. I couldn't get to the shares it kept asking for a user name and password even though i had a user already setup. So i setup a new user on that machine with no password. I still could not get to that machines shares, I added a password and all of a sudden every thing just started to work.
This was also the same with another network i setup with two vista machines trying to talk to each other for the exact same scenario.