Windows 7: Media streaming empty libraries

I am struggling to get internet media streaming to work between my home and flat PCs.

Windows 7 clean install onto a 160Gb HDD with a 250GB data drive.
2x users (1x admin, 1x standard).
Admin user my music, vids and docs moved ( as installed, empty) to 250Gb drive.
Library includes the public and data drive (users/rob/music)
Music copied to 250Gb drive my music from NAS backup storage.

Can see and play the music in media player on the home PC.
Homegroup setup with son's PC. sharing enabled, cannot see music in my library, only way to make it work is to watch the 250Gb drive directly from his media player.

Setup media internet sharing using live account. Flat PC media player can see internet share in other libraries, computer named correctly, music folder empty with no files.

My gut feeling is that the moving of the folders initially has cocked this up, but how do I fix it? Any thoughts?

Rob