Cannot permission a user on a wireless network?!?!

[bogstick]

I have a simple home network set up with a PC connected to a router and a laptop connected wirelessly to the network.

There have been no problems with full access by either machine to each other (set up through File Sharing).

However, I have now decided to now only give specific access ie. permission the laptop to have access only to certain folders. For example, i select a folder on the PC and then go inside the appropriate network tabs/ properties to where users are permissioned.

The problem is I am unable to see the laptop's users in order to add them???
The only users i can see are the standard default ones on the PC ie Everyone, Authenticated users etc

I hope i have provided enough information as wanted to keep it brief enough to the experts here...

Hope someone can help?

Thanks