I don't know if anyone has had this or would even know where to start. I have two PC's, both Win98, networked just peer to peer with a crossover cable and 3Com 10/100 nics. When mine is on and my girlfriend turns hers on. Mine locks up. If hers is on and I turn mine on everything is fine. If we boot at the same time everything is fine. Like I said WIN98se, Peer to Peer, 3com 10/100 nic cards. So nothing too difficult as far as configuration.
I'm pulling my hair out.

Thanks in advance.

I'd start by checking all the settings for the protocol your using.
They should match exactly. Except for the Identification tab.

I'd also check the bios making sure that the Boot From Network is Disabled in both systems.
If they support it.