When your Toshiba L775 is not showing the F2 option on the first screen after you have pressed the power button, disconnect the charger, take out the battery, open the small plastic cover as shown in pictures bellow and remove the small battery for about 15-20 seconds. After that, make all the operations in revers order and power on the laptop: now the options F2 and F12 should be in the right place so you can enter the BIOS or the boot menu.
