Wireless WLAN Card problems

I recently bought my daughter an Inspiron 1011 and set up a wireless network connection to existing Broadband and all was working fine until today. She said she "accidentally" changed something and now all I get is an error message saying "The Dell Wireless WLAN Card is still disabled. Slide the Wireless ON/OFF switch to enable it". However there isn't an obvious ON/OFF switch and I tried FN2 function hoping that this might help but it hasn't.

Any help gratefully received!

Steve