Please provide the full output of the inxi command previously given; it will allow a greater depth of system information which may reveal other contributing issues.
This is the mimimum information usually requested; here is an inxi command in long form:
Guys, there can also be the problem that the disk is full. Hence some packages might be partly installed or not at all. Output of df -h in a terminal can give a clue about that case. Also check if you see some issues within /var/log/pacman.log of the last update you made. XFCE tend to show just a black screen when it has no space to write stuff …
Those empty files should not be empty. Which means crucial system packages are broken and the kernels were the tip of the iceberg. Maybe a partial upgrade? Or a hard reset and damaged filesystem? I don’t know.