Please post:
ipconfig /all
ping
your default gateway (you can get this from ipconfig /all, it will be the same default gateway as your XP machine)
ping www.google.com
tracert www.google.com
You don't have Symantec Antivirus installed, do you? Sometimes the firewall service gets corrupted and then blocks everything out on port 80 and 443.
You may want to put a USB into the computer and get the output of the commands by redirecting output to a text file. You could then edit your question with the results. Example:
ipconfig /all > e:\ipconfig.txt