Crap! HDMI... :( Help!

[kitepilot at kitepilot.com]

In my infinite wisdom, I bought yesterday a laptop (Asus ROG GL752VW) and a 
4K TV to use as a monitor.
Stupid Windows 10 would not detect HDMI. 

OK, screw it, I'm going to dual-boot the thing anyway.
Well, latest-and-greatest Linux Mint (KDE) doesn't detect the HDMI either... 
:( 

So...
I bought a 'mini display port-to-VGA' adapter and plugged it VGA into the 
TV.  It works, but I only get the same laptop resolution (1920x1080)
...
8-( 

So...
Questions are:
1.- Can I expect my full 4K resolution if I get the #$@! HDMI working?
and
2.- What can I do to get the #$@! HDMI working?
Thanks!
ET