Can i play shadows of amn LAN??????????/
and how

Yes, you can. If you have a working LAN its pretty easy. Start BG2 on the more powerful computer, go into the multiplayer and create a new game using tcp/ip . Start of the other computer(s) and join a game on tcp/ip , and when it asks for an IP address give it the address of the host computer.

You can find the IP of a computer by start->run->winipcfg , select the ethernet adapter (or whatever *isnt* listed as a PPP adapter) and note down the address. Its a 4*3 digit number, usual 192.168.0.X or 10.X.X.X depending on how your system is set up.

be sure all participants got the same version and possbible mods.
make sure all configs got the same AI footstep value.

Make sure everyone has the same versions, patches, mods, etc., and that they're all installed in the exact same order as everyone else's. Things won't work right if they're not.