New
#91
Why would you mark Win7 partition as Active before rebooting it if it hadn't needed repair?
If this is what you did then it may be that you have the 100mb System Reserved partition and when you changed the Active flag from that System partition (which is booting Win7) without also running the repairs, it would be expected to receive Bootmgr is Missing error.
If so then move the Active flag back to 100mb SysReserved and see if it boots outright. If not run Startup Repair - Run 3 Separate Times until Win7 boots and the System Active flags are both on 100mb again.