Unknown user name or bad password

"Login failure: Unknown user name or bad password"

Two machines, 'A' and 'B', both running W7 sp1 x64,
Both have the same username & password,
Both are setup to share all drives,
Both are using the hidden (or super) Admin account renamed (by design),
Both can see one another, all drives, all folders,
No firewalls.

Initially 'B' could logon to 'A', but not the other way around. A search found the problem under Advanced Sharing. The 1st two entries were turned off. Now, 'A' can logon to 'B', but not the reverse which is opposite of what it was before.

As soon as I try to connect, before I even type anything in, the message in the logon box is the above "Login failure".

Nothing was done to 'B' where it initially worked before. Is this some one way deal, logon one way or the other, but not both?

You shouldn't even need to use the same user name and password to access each other both ways.

You don't need to use the super Admin account for this.

You should not need to turn off the firewall for this simple sharing to work.

I can't imagine how these shares aren't working because you have done more than is required so most likely a windows service is turned off or there is a third party anti virus software involved.

Have you tried setting up a Homegroup between these machines?

Using the same user name & password is not just convenient, but logical (less confusion). The hidden Admin account removes 75% of the annoyances of W7. It just makes trying to use W7 somewhat easier.
No 3rd party firewall.
No on Homegroup, no intention to use it.

Nothing was changed in 'B', the change was with 'A' affecting 'B'.