Hi Rockface,
May I know the system model and the Operating system installed on the computer?
Did you try uninstalling and reinstalling the wirelss card drivers?
If not, uninstall and reinstall the wireless card drivers on the computer.
Check the status in Safemode with networking. Restart the computer and tap F8 on Dell logo and select Safemode with Networking (Windows 7).
Awaiting your response!