How to enable auto IP Renewal in win xp?

[Shadowfire]

When i turn my comps up, i get an auto IP setup at 168.x.x.x, but when my main one connects online, the IP's change to 192.x.x.x.

Now since the main one is the server, the IP's renew automatically, but my sister's comp is still stuck on the old IP's, and will renew only if i click "Repair" on the connection status window. How to i tell windows to automatically repair it? OR at least detect new IP ranges?

[Spineshank]

Try going to command prompt and typing ipconfig /release and then ipconfig /renew and see if that helps any.