Can you be specific and tell what you're trying to do? You can't make a bootable installer CD of Windows XP Home Edition that is currently running, if that's what you mean. If you need to make a bootable installer CD, you will need to get a replacement from somewhere.
There are a couple of things which you might want to look at here: 1. Are you sure the IP address of computer B is 192.168.2.1? If you don't have a DHCP server service running somewhere, you'll need to assign static IP addresses to computers A and B. 2. Make sure you don't have a blank password for the account(s) that you're using for remote desktop. Windows XP doesn't like blank passwords over remote desktop If you've got high speed internet (cable, DSL) then it might be easier for you to get a home router. Those are very inexpensive and relatively easier to set up.