@RodrigoN, if your kernel version (which can be displayed in Terminal via uname -r command) is below 5.0.x, and your initial Ubuntu distro was 18.04 or 18.04.1, you don't have HWE installed. As stated here:
"The [HWE] stack consists of a newer Linux kernel [meaning, v5.0], X.org graphical server, and graphics drivers. These weren’t automatically installed on existing systems <...> If you installed Ubuntu 18.04 using the Ubuntu 18.04.2 installer, you will automatically get the Ubuntu 18.04.3 update featuring the new Linux kernel. If you installed Ubuntu 18.04 using Ubuntu 18.04.1 or the original Ubuntu 18.04, you won’t automatically get the new Linux kernel."
To install HWE on Ubuntu 18.04 desktop PC, execute:
sudo apt install --install-recommends linux-generic-hwe-18.04 xserver-xorg-hwe-18.04
