Hi,
Thank you for posting in Microsoft Community.
I understand that the TV tuner is not working in Windows 8.
1. Are you using External/Internet TV tuner?
2. What is the make and model of the TV tuner?
Please follow the methods.
Method 1:
You can try using the Hardware and Devices troubleshooter to fix the problem. It checks for common problems and makes sure that any new device or hardware connected to your PC is installed correctly.
Open the Hardware and Devices troubleshooter by swiping in from the right edge of the screen, tapping Search (or if you're using a mouse, pointing to the upper-right corner of the screen, moving the mouse pointer down, and then clicking Search), entering hardware and devices in the search box, tapping or clicking Settings, and then tapping or clicking Find and fix problems with devices.
You might be asked for an admin password or to confirm your choice.
Method 2:
a) Download the TV turner driver from the manufacturer’s website.
b) Right-click on the driver and click on properties.
c) Click on the ‘compatibility’ tab and check the box "Run this program in compatibility mode for” and select Windows 7 operating system from the drop down.
d) Click on ‘Apply’ and click ‘OK’ and run the file to install it.