there is no switch as such, yours probably uses the atheros which i dont get on with.
there is a setting in bios that may be dissabled.
if your using vista then open control panel\network and sharing centre\ left hand column manage wireless networks
then adaptor properties make sure it isnt disabled.
now from good old xp
control panel\network and make sure nothing is disabled
now who said pista was suppose to save time and be user friendly!!!