Android sdcard appears empty to Windows?
I've done some research and it seems to be an oddity of the tablet. 

When you do 'move to sd' whats happening is its moving data to another part of the -internal- sdcard. You can't move apps to the external one

e.g.

http://yatse.leetzone.org/redmine/boards/2/topics/259#.UTfGXxyeN8E

thanks anyway