Do you have a spare HDD on which you could install fresh Windows to check whether GPU-Z works on a new install on the same system?
It'll take a few hours to get everything ready, however, as I need to rig something up to support the mobo, etc., as I don't have a spare case nor really want to use one.
^ This. Although, I still recommend a fresh install anyway as 1709 was a major update and fresh installs are historically more stable and less problematic.
EDIT - I thought my reply didn't post so posted another and the forum decided to edit this one... so, something is borked with the forum, too...