Perhaps you have to add the ppa of hauppauge to get your tv tuner card to work? Before doing this please disable secure boot in your BIOS. In the link you can see which cards are supported.
It could be also a problem with wayland that is used in Zorin 17 core by default. Caffeine makes problems with wayland.
You can switch to Xorg. Logout and at loginscreen click on your username then a cog appears on the screen. There you set "Zorin desktop on XOrg" and then enter your password to login.
But I'm not sure if that helps. There are problems reported with caffeine on Z17: