I'll go through the (somewhat lengthy) history of this problem, to avoid the scenario where too many further suggestions / requests are needed.
I have ...
2 XP boxes,
tried SP1 and SP2 on both at the same time and different times,
done full reinstalls of the OS's,
tried the maf'rs drivers as well as MS's,
Swapped out each NIC (which I've tested indepenantly),
Swapped out the x-over cable as well a tested what was used,
Run the winsock fix for XP,
Allowed XP to assign IP's,
Assigned static IP's,
Reduced the network speed down to its slowest level as well as full auto,
Pinged until I couldn't ping no more and renewed and released for England.
The problem is that I cannot get the 2 boxes to talk, or rather I can have a one-way ping where box 1 sees box 2 but not vice versa. If I allow them to assign their own IP's I get the self assigned 169.x.x.x. If I assign them manually (192.168.0.1+ for example), then we still don't have any joy.
DHCP is enabled and neither machine is firewalled.
Of further interest may be .....
1. Box 1 didn't always autodect the NICs I was using. PCI slot didn't seem to matter, but sometimes it detected and others it didn't (and it wasn't going to be forced with detect HW wiz).
2. When I ran SP2 on box 2 I got the yellow ! with the low / no connectivity warning.
The plan was to set ICS on Box 1 and share the cable (non ADSL) connx to enable box 2 to access the internet. As you are now aware this was scuppered before it got off the ground as I can't get these 2 boxes to have a conversation for love nor money.
Any help greatly appreciated, otherwise they're both going to the bottom of a lake with a millstone around them.