Computer stalls when networked

I'm attempting to give my laptop network access, and I started by buying a PCMCIA network card. After a lot of hoohah, I managed to get it functioning at least the slightest bit. I have been able to access my desktop and take files off it, through the Explorer interface. The problem is, sometimes, seemingly intermittently, the laptop will freeze/stall/lock up when the cable is plugged in. I've installed all the protocols, the proper drivers etc, as well as reinstalling Windows. Is anyone familiar with this problem.

Laptop:
HP Omnibook, Windows 98 SE
ST Labs PCMCIA NIC

Desktop:
Windows XP Pro
Realtek NIC

It's probably just a buggy driver. Did you try another NIC on it? Also, it could be you set it up on a port that's conflicting with another device - try setting it up on a different one (make sure that the proper IRQ is associated with that port, too).