For all VAIO issues with the wireless switch not working after downgrading, reinstalling or updating.
Do the following:
1_ Disconnect the power cord from the VAIO laptop/netbook
2_Shutdown the computer via START/"shutdown option"
3_Remove the VAIO laptop/netbook battery, wait for 3-5 minutes
4_Put back the battery, make sure the wireless switch is on
5_Connect the power cord, if you need to, then turn on your computer.
6_Drivers will finally install properly(you will see the popup notifications), wait until it is done, then the wireless light will come on...That's it !