Booting Ubuntu 20.04 on Intel CPU causes reboot

Solution 1:

Ubuntu 20.04 currently comes with the 5.8 (1st HWE Kernel for 20.04) Kernel. You must have somehow installed 5.11 (2nd HWE kernel for 20.04) manually, 5.11 will only be used by default around the 20.04.3 update (~August 2021).

Also on Ubuntu on Intel or AMD there is virtually never a need to “install Mesa drivers”, they come with Ubuntu and are automatically updated and managed. If you need newer Mesa you can install a PPA, but that isn’t recommend or supported, and PPAs can absolutely cause problems like this one.

I would generally recommend not using VGA, but it should still work. If possible try out other ports on your motherboard.

Please try Ubuntu 21.04 which comes with a newer Kernel and Mesa by default, no configuration required. If that works perhaps try 20.04 again, ensuring you go for a very “default” installation.