He is correct you want to install IPX/SPX and netbui on both machines, to share files.

Alos make sure that the logins that you and your bro us have adminstrator priligages.
And like he said make some shares and bingo bango you should be able drag and drop files between the computer and should should not have to have a firewall on your computer the router should have somthing called NAT(network address translation) on it. Basically its a pain in the ass to get past. So you dont really need to have a fire wall on your machine if the router does have NAT. The worst that could happen is they mess up your router and you need to set it back to factory defaults.

so go have fun