I have a newer P755-S5263, my wireless stopped working this morning. Other computers in the house have no problems connecting to the network. The F8 function says the wireless communication switch is off. I have looked all over for one and cannot find one.
The FN+F9 is to turn the touch pad on/off, changing the settings there did not seem to help me at all. If I press the FN+F8 it will not toggle the wireless on or off becuase it says that the wireless communication switch is disabled.
Have you looked through the user guide?
Having looked at a picture of a P775 you have a panel above the keyboard with a power button and a series of some sort of indicators including volume + / -. I would guess these are touch sensitive and if there is a "wireless" icon on the panel then I think that may be the button.