My laptop has symbols on all the function keys, I know f7 &f8 are to increase or decrease brightness but I don't know what the other ones are for. Also why do these not appear on my main pc keyboard? Thanks for any help.
Though to be fair it doesn't answer the last part, of why they are not on a desktop PC keyboard.
to which the simple answer is, you haven't got a multimedia keyboard, if you did have one then most of the same controls would be on it but they'd be on their own keys (due to having more space available). the brightness wouldn't be on there as that is adjusted on the monitor, not the computer. (and on a laptop obviously the monitor is part of the computer)