I just checked the User's Manual for the ASUS F3F, and there are three types of external video connections.
S-Video: a small round connector with 4 to 7 pins.
DVI: a rectangular plug with 18 to 24 pins arranged in three fairly straightly aligned rows; or
VGA: a 15 pin "D shell" type of connector. The pins are in 3 staggered rows.
The connector you use may affect the method you use to enable it. The connector you have been using may have gone bad, so try another type of connection. Many new TVs have two or even all three of those three connections.
Also, according to the documentation, to switch between monitor modes you use the <Fn>+<F8> key.
If you look closely at the faint blue icons on those F-keys you will see a small [LCD]/( ) (two types of monitors separated by a "slash") to remind you what the blue <Fn> function is for.
The manual also reminds you to connect the external monitor BEFORE turning power on. (Probably for equipment safety, but it might be that the port being used is tested at startup, so if it is not there at startup then it may not get enabled later.)
I have a ASUS F3F running MS Vista Home Premium. I bought a Vizio 22" TV and connected my laptop to it to watch vids etc using RGB. It worked great for about 6 months then 6 weeks ago I went on a trip and took my comp with me. When I hooked it back up I cant get it to work. Somehow the info on what to do to the PC that was stored in my 74 year old brain can't be recovered. Can anyone help me? I tried the FN-F4 procedure but all I get is Real Player.