WinXP networking troubles

I have a DSL broadband connection going to a Switch, which goes to my Xbox, my roommates Mac G4, and then to NIC 1 in my Computer A (a PC). I then have a network cable going from NIC 2 in Computer A to a NIC on Computer B (also a PC). Both Comps A and B are running Win XP Pro. I can't get Comp B to connect to the internet when sharing the internet connection with ICS from NIC 1 on Comp A. The wizard is not helping, and I am darn sure I know what I am doing. Even with all the cables connected, Comp A NIC 2 is showing "A network cable is unplugged". The same is showing with the NIC on Comp B. This is very weird here: one time, after disabling all proxy server usage on Comp B, I restarted both computers, and Comp B was able to surf the internet, but not check email or connect with Messenger Services. Comp A remained connected to the internet with everything working. Both Comp A, NIC 2 and Comp B's NIC showed "A network cable is unplugged", even though Comp B was able to surf the web. I can't make this happen again. What is going on here? and what can I do to get Comp A and B to communicate and share the IC???
thanks....

Are you sure you have a crossover cable going between the two NICs on the PCs? You can't use a normal cable between two NIC cards.

i am using a crossover cable.....it's so strange....i got it to work again where only Internet Explorer was allowing some surfing on comp B, but still not email or Messenger services.....still perplexed!!!!.....i created a bridge between the 1394 adapter and my NIC 2 successfully on comp A, and now the NIC's no longer say, "A network cable is unplugged" on either comp....so the comps are connected....are there some settings i'm missing here?

on comp A, add bridge between both NICs/nets