Im using a belkin and had exactly the same prob as you last week when I had to totally reinstall XP on my laptop.Spent hours farting about,using the same settings but could not connect.I then resorted to the helpline and the initial automated message told me to unplug the modem and router and then reattach.I did this and all was well!
I then did not know how to secure my network so had to phone them anyway..
The helpline is a pain as you can be waiting for ages but they take your number and actually call you back (11;45pm in my case)-presume they are international as I had great difficulty explaining to and understanding the Asian soundin guy on the other end.I found the interractive setup on their website does not actually reflect what happens when you follow their steps..It apparently needs updating and I had to be given info over the phone that is still not available on their site.
Hope thats helpful.
Edit..
My network consists of 2 laptops,mine (the master one) detects as soon as I switch it on.To connect to a network I go to network connections and click search available wireless networks..yours should then be detected if your laptop has wifi enabled-all you do then is click connect to network and if required enter your network key.If you have forgot the key then please say as that was what happened to me..then I'll try to describe how i got around that.