Win10 Upgrade failed - Black Screen, no backup image - What next?

I foolishly allowed Windows to upgrade to Win 10 without thinking of backout options. I have a Win7 repair disk for the PC from a couple of years ago but now the PC is showing nothing on screen and Win 10 as the OS when booting from the repair disk, it seems I can't use it to solve the problem.

I think I have updated the video driver for the monitor, but to no avail.

Any ideas?

i had this problem after trying to revert back to win 7,in the end i had a spare hd i put in then used my win 7 recovery disc to install on it , i also have a hd docking bay so i could still access the drive,hope this helps.