Vista Home & Windows 7 - Shared Folder Problem

Hello - I’ve been unable to configure sharing on my home LAN to meet the following objective:
Share folders that reside on the Vista Home PC with a Windows 7 PC. DO NOT share Vista or Windows 7 folders with the Apple PC; rather block the Apple PC from any access to Vista or Windows 7 computers/folders.
Background
My home LAN has 3 PCs on it:

1. Vista Home (Used by me)
2. Windows 7 Premium (Used by wife)
3. Apple (Used by child)

What I’ve attempted/configured on both Vista and Windows 7:

1. Workgroup = WORKGROUP
2. Firewall “printer and file sharing” - checked.
3. Attempted to follow these instructions: Sharing Between Windows Vista and Windows 7 Computers

I was unable to turn off password protected sharing on the Vista PC ? I set it off but it always resets immediately to on?
FYI - my PC skill level is medium. Any help in reaching my “objective” would be appreciated. Thanks.