What is the reason for your NAS drive? To share files between computers?
I always think that it is best to have all files stored centrally on the NAS and not on the computers. It may take a little time to set up but would be well worth it.
For example - I have my Itunes library stored on my NAS and I have set up Itunes on all three of my PCs to point at this. Therefore I can change my library and sync my ipods on any of my computers.