On an Acer, you usually press <Fn> + <F3> keys.
Otherwise, press <Fn> then press the key with bluetooth symbol on it.
Picture of bluetooth symbol here: http://www.google.co.uk/imgres?imgurl=http://www.artistsvalley.com/images/icons/Professional%2520Vista%2520Software%2520Icons/Bluetooth/256x256/Bluetooth.jpg&imgrefurl=http://www.artistsvalley.com/previewicons-Professional-Vista-Software-Icons/bluetooth-icon.html&h=256&w=256&sz=83&tbnid=GSUTnp3T_Idq7M:&tbnh=91&tbnw=91&zoom=1&usg=__-8QOWCtmOqBGOzI_QAhQ7mt3Tc8=&docid=aaLTmCKvD6-WOM&hl=en&sa=X&ei=NnAmUbjpMOK80QWQyIHYCw&sqi=2&ved=0CEIQ9QEwAw&dur=519