Let me start out by saying I am completely and totally ignorant when it comes to wireless connectivity.

Now... my wife's netbook won't connect to the internet. It connects to my wireless home network (5 bars, 54Mbps), says it is connected, everything looks happy. My neighbor downstairs connects to my wireless network (a WRT54G router connected to a cable modem) and has no trouble with internet connectivity. SWMBO's netbook used to connect to the internet, then last week it stopped.

When I load Internet Explorer and attempt to connect to Google, it waits a while and then gives a big message about "Cannot connect to the Internet." Following the troubleshooting guide, all it comes up with is that perhaps there is a problem with firewall settings and to check ports 80, 443, and 21. I have disabled all firewalls (Windows and AVG) and still the problem persists.

This is as far as my [very] limited wireless connectivity knowledge can take me. Where should I be looking for a solution?

The netbook is a Samsung NP-NC20 running Windows XP.

tanstaafl.