Are you using any security on the link WEP or WPA ?
Do you have any connectivity to the Internet - I.e. try a ping to
www.bbc.co.uk from a command prompt.
You could try resetting the TCP/IP stack before reinstalling ;
1. Go to Start Menu -> RUN
2. Type "command" click OK
3. In the new window that pops up type this "NETSH INTERFACE IP RESET LOG.TXT" (less quotes), then press enter.
4. Reboot, if you like.
More detailed information can be found in this MSKB article:
How to Reset Internet Protocol (TCP/IP) in Windows XP (Q299357)
http://support.microsoft.com/?kbid=299357
Just some random thoughts.