The PCI express error is not related and was not because the motherboard was
faulty, it is a bug related to the Skylake CPU series.
I applied the workaround described here:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1521173
I understand and already did what you suggested, but i thought
Your disk is currently partitioned to boot in bios mode, but you booted
the 16.04 installer in EFI mode. A warning message prompted you that
this could be a problem and recommended performing a bios mode install
instead, but you chose not to. You either need to perform the bios mode
install, or
