[Ryanoffski]

Originally posted by excuzzzeme
It means that Your IP is shared by another computer on the same network. Has nothing to do with nic vs modem nor your ISP. No two computers can have the same ipaddress on the same network. To correct, do as "dave" instructed.

If you still can't get on or renew you need to make sure you have DHCP enabled. To check :

Right click "My Network Neighborhood"
"properties"
right click Local Area Connection
"properties"
highlight "Internet Protocol (TCPIP)"
properties
clikc the button "Obtain IP address automatically"
Same for "Obtain DNS address automatically"
close all windows normally
re-boot

Upon restart:
Your system will then negotiate for your Ip with the router that serves your network.
If you still cannot get on it is likely that IP's are assigned statically and you must see the system administrator for access.

Though with Windows XP you shouldn't need to reboot. As soon as you click ok it will change and obtain the IP from the router.