Half Life 1 and XP

Any idea on what settings i should use to get this running? Half Life 1, from the original disc, with WinXP Pro SP2

HalfLife cannot go "ingame"

Wait, have you tried playing the game on your own without connecting to his game? HalfLife has a serial, and you can bet your tight ass that it's comparing serials across the network.

Disconnect your XP box (just to be certain), and see if you can play a normal single-player game of HL.