Usually it's permissions issues on the folders (and the files contained therein).

The sharing would have had issues regardless of the OS, I'm thinking that the reason things worked before is that you had the same user account on both PCs before. And now, it's a different user account trying to access it from the new machine.

So in addition to setting the rights on on the share, you gotta set the rights on the folders and files too.
_________________________
Tony Fabris