HDMI out not working on X340?

I picked up an MSI X340 laptop last week and have been using it without any issues with VGA out to a 58" Samsung PN58B540 screen. However, I wanted to use HDMI instead (is it higher quality video?) and to hook up the laptop's audio to my receiver, so I hooked up the receiver to the TV's audio out via an optical cable (works great for BluRay and Xbox - they're both hooked up to the TV via HDMI and the TV sends the audio to the receiver), and then bought a new HDMI cable with the intention of hooking the laptop up via HDMI instead of VGA, so that the laptop would output the audio via HDMI as well, and the audio would pass to the receiver through the TV. First question: will this audio setup work? Second (the main one): HDMI out for video doesn't seem to work - the laptop recognizes the TV as being hooked up, the HDMI port in use lights up on the TV's menu, but when I actually select that HDMI port as the video source, it says no signal. I've tried using different HDMI ports on the TV (the laptop has only one), but the exact same thing happens. What's the issue here? Thanks!

 

Nevermind - fixed by pressing FN + F2.