heres my input:windows xp has a built in firewall, so you have to make sure that it is turned off. it is under start-control panel-network and internet connections-network connections-right click on local area connection-properties-advanced-make sure that internet connection firewall is not checked
also:check your tcp/ip properties and make sure that you have obtain ip address and obtain dns server automatically
as far as the user name and password not being set, just curious if by chance you are getting a error 678 on the computer when trying to connect, um my email address is
[email protected] if you need more help
oh and about changing the ip address:go to start-run-type in command to get to the command promt, then type in
ipconfig ( gets your ip address, subnet mask, and default gateway )ipconfig /release (releases ip)ipconfig /renew (renews your ip)
hope this helps
fabian