What encryption method are you using? WEP? WPA? WPA2?
With WEP, you must enter WEP "key 1" (found in the router) into your computer, not the WEP password or passphrase.
With WPA or WPA2, you must enter the key (sometimes called password or passphrase) into the computer.
For WPA or WPA2, you either need Vista, or you need Windows XP with SP2.
Also, Windows XP requires a patch to run WPA2. Go to Microsoft Knowledge base, article ID=917021 and it will direct you to the patch. Sadly, the patch is not part of the automatic Windows XP updates, so lots of people are missing the patch. You must have SP2 installed before you install the patch.
Also, in your computer, temporarily turn off the software firewall, including Windows Firewall, and see if that helps.
Message Edited by toomanydonuts on 02-28-200803:41 AM