Dell Inpsiron 560 (Late 2009) - Manual (Page 157)

Networks (LAN, Wireless, Mobile Broadband)
157
Enabling/Disabling the Wireless Card With a Wireless Switch
Your laptop computer may include a wireless switch. You can use this switch
to turn your wireless card on or off.
NOTE:
By default, the wireless switch is turned Off while shipping your computer.
The wireless switch must be turned On to detect and connect to a wireless
network.
On some computers, you can also use the wireless switch to scan for a wireless
network by sliding and holding the wireless switch in position for a few
seconds. Other computers may use a separate button or switch for scanning.
FOR MORE INFORMATION: To learn more about how to find out if your
computer has a wireless switch and where it is located, see your
computer’s documentation.