I was unable to access a folder on a Win7 Home Premium PC from a WinXP Pro SP3 PC even though the user accounts on both PCs were in the same workgroup and had identical names. Also I had done the following:
Use Control Panel > Network and Sharing Center then...
click "Choose homegroup and sharing options" then...
click "Change advanced sharing settings" then...
scroll down to HomeGroup connections and press the following radio button:
"Use user accounts and passwords to connect to other computers".
The key step I had overlooked was to apply a password to the user accounts on both PCs.
I'm writing this because the requirement for passwords on both accounts hadn't been emphasized enough in any of the references I had consulted. The info may have been there, but it just didn't sink in.
Since I am a relative newcomer to Win7, I stand ready to be corrected. If you know of a way to give read/write access to a folder on a Win7 box for a specific user on a WinXP box (and ONLY that specific user) without having passwords on the user accounts in both machines, please let me know.