Couple of things I would check..
1. Check the router itself to see if Wireless is enabled
2. Check that your laptop "sees" the wireless router. You should be able to do something like "View Availible Wireless Networks", make sure your's is being seen.
3. That your PC/laptop is getting an IP address from the wireless router. Go start->run then type cmd to get a command window. Type "ipconfig" at the DOS prompt. You should see an IP address (something like 192.168.0.2. if you see 169. instead of 192 you may have a problem with DHCP - the protocol that assigns IP addresses).
4. If you do have a 192. address then try the following from the same command window. Type "nslookup www.yahoo.com". This should tell you if you are connecting to DNS......
C
Documents and Settings\Owner>nslookup
www.yahoo.com
Server: BThomehub.home
Address: 192.168.1.254
Non-authoritative answer:
Name:
www.yahoo-ht3.akadns.net
Address: 69.147.114.210
Aliases:
www.yahoo.com
C
Documents and Settings\Owner>