I recently upgraded my father's laptop from Windows 7 to Windows 10. A few days later he tells me Windows won't start.
I get a "The Windows Boot Configuration Data file is missing required information" screen.
Since I only had the original Windows 7 installation disc, I tried to repair the boot with it. Did the usual bootrec commands (fixboot, fixmbr, rebuildbcd) and got the same error again. Booted from the disc again and it listed both Windows 10 and Windows 7 as available systems, and bootrec /rebuildbcd now returns 0 available operating systems.
How can I fix this now?