Hello alk91,
Assuming you're asking how to connect your Windows XP machine to your wireless network, you'll need to enable the wireless network adapter on your computer (given your computer has a wireless adapter).
To do so, go to your Control Panel --> Network Connections --> Adapters --> Right-click on your wireless adapter and click 'Enable'. This will turn on your wireless adapter and allow it to find your wireless network. From there you'll need to click 'Connect' when you see your network and enter the security key (if enabled).
However, since we're working with Windows XP, there is a possibility that your wireless adapter is looking for a wireless 'G' network. Your Netgear, by default, will broadcast a wireless 'N' connection. If this is the case, you'll need to enable the wireless 'G' radio on your Netgear router using the web browser interface.
Let me know if this helps.
Cheers!