I would be very happy just to share the folders on the drive directly. (Also, I called the drive 'external' when I really meant 'additional' - it is drive E: on the internal SATA channel). I have applied shares on the root of Drive E:, on several of the folders themselves, and even on a file or two, just to see what would happen. The system seems to share them properly, rolls through setting permissions, etc. Then, from any other computer in the workgroup, the shares show up just fine, but Windows 7 stubbornly refuses to open them. The message is "<\\computer name\folder name> is not accessible. You might not have permission to use this network resource......access is denied." No offer to enter a user name/password, or anything else. Just plain 'denied'. I had no problem like this with the same setup on an older WinXP3 desktop so I am really baffled.
My adventure with libraries and public libraries was an alternate attempt to make my E: drive available to the workgroup. I found that, once again, adding various folders to a library just created a shortcut which would not open in W7 Explorer. The message is "<path> is not accessible ... access is denied". Also, the system will not allow me to place my folders into a Public directory, except for, oddly enough, one called simply "Music".
I am loath to go further and try to set up a Homegroup, since I see there are major complications if other machines on the network are Vista or XP.
This is quite frustrating, so any other advice would be helpful. I must be missing some fundamental point.
Thanks in advance for your help so far.