Help with file sharing on Windows Vista (right click leads to adva

So when I right click on SOME folders and click share, I get the File
Sharing screen, which is what I want @
http://technet.microsoft.com/en-us/l...echNet.10).gif

Folders shared with this method are accessible to my other computers.

But when I right click on OTHER folders and click share, I get the Advanced
Sharing screen @
http://technet.microsoft.com/en-us/l...echNet.10).gif (also share button on that screen is faded out so I can't click on it)

and even WHEN I try to configure folders with the advanced sharing screen, I
can't access those folders from my other computers.

Is there a way to force the share button to direct to the File Sharing
screen? (for any arbitrary folder?) Thanks!