Sony VGC-LS1 Series User Manual page 86

To disconnect from a wireless network
Turn off the WIRELESS LAN switch.
!
Turning off the wireless LAN functionality while accessing remote documents, files, or resources may result in data loss.
For WPA-PSK or WPA2-PSK authentication, you must enter a network key of 8 to 64 alphanumeric characters long.
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Using Your VAIO Computer