What methods did you use for connecting TV? Many system don't recognize and reroute display signal to TV automatically. You have to activate the port by changing your display setting.
Right-click on desktop (windows background screen)
Click screen resolution, or nvdia/any other specific display driver name
If the second monitor (TV) doesn't show up, click detect
Click the diaplay drop-down menu
Select your TV, or dual display
On TV, what input did you select? There must be HDMI 1, HDMI 2, ...
You may need to download display driver, but since the PC already have HDMI, it must have driver for that. Read the owner's manual for display section. You can find more information specific to your PC.