Hello and welcome to TSF...
we need to know what model you have:
http://h20180.www2.hp.com/apps/Looku...=12&submit.y=7
Usually you start WLAN with quick launch HP buttons... if you did not install HP Quick launch buttons driver, you have a issue...
Go to Network Connections in Control Panel and check if WLAN card is enabled or disabled...
Well, maybe you should tell us do you have any yellow question marks in Device Manager?????
Keep us posted...