I'm not familiar with that model (my laptop cert's were IBM and Toshiba) but things I would check aside from the obvious (the wireless switch is in the On position - providing it actually has one):

1) Open Device Manager (Windows Key + Pause/Break key to open System Applet >> click on "Hardware Tab" ->>click on Device Manager) and check to ensure the wireless interface is working properly in there. If it has an exclamation mark, there's a problem and at this point you should go to Step 4 and try it.

2) If it shows the interface is working properly according to DM, I would next ensure the wired interface (or interfaces if it has more than one) are disabled. Go to: Start >> Settings >> Network Connections and right click on the wired interface (usually "Local Area Connection") and select "Disable" from the menu that comes up. If it starts working properly, you're done.

3) If that didn't fix it, check on HP's site for updated drivers for the device. You'll need the model number off the bottom for sure for this. If there are updated drivers, download and install them.

4) If updated drivers don't fix it (or there aren't any newer drivers) you may want to try uninstalling the device itself in Device Manager. To do so, open DM and find your wireless network interface again and this time right click on it and select "Uninstall" and reboot. Windows should "find" the device upon bootup and reload it.

5) If none of the above get it working properly the last thing I can think of trying is to unistall, then reinstall the TCP/IP stack on the device itself. To do this, go back to Network Connections (Start >> Settings >>Network Connections) and on the wireless connection right click and select "Properties" from the menu that comes up. In the window that opens scroll down to "Internet Protocol (TCP/IP)" and click on it to highlight it and select uninstall. Reboot, go back into the properties for the wireless interface and then reinstall the same TCP/IP Stack. Reboot again and see if it doesn't start working.

If none of the above works, the interface itself is either broken, or you'll need to take the unit in to HP to be fixed. If it's not under warranty, it's likely not worth it. It would probably be cheaper to buy a PCMCIA wireless ethernet adapter for the unit (providing it has a PCMCIA slot or two).