Solution posted by devnull (from Microsoft support) is for both x386 and x64 systems. Maybe that difference (most of us have 64 bit OS, but not all) prevented somebody from successfully revert...

It will be real problem to install it, since users that have non working systems will most probably find other ways..

One more queston devnull: did you try the top two USB ports in the back of the...

Zbook, Thread starter doen't have PS2 ports on his computer. More and more this seems like mission impossible.

Perhaps time to consider making backup, but computer refuses to boot from USB....

If moving display from discrete to integrated graphic enabled you to access BIOS, your graphic card could be damaged. Nevertheless, try this first:

- In BIOS (UEFI) check if your USB ports are...

If you want to boot from USB media and don't have the means to change boot order, disconnect internal drives, so only USB will remain.

Looks like your BIOS / UEFI was reset, or motherboard is...