I tried to upgrade the computer to windows 7 via online downloads from microsoft and now I have this bootmgr is missing message upon startup. Any way I can fix it? I’d like to be able to still have windows 7 if possible...
So are you able to get into windows 7 right now?
If so get easybcd it's an easier way of editing the bcd store which you could do with console commands.
Get the free version and watch some tutorial if you have trouble,basically all you hae to do is to go to the BCD deployment tab and write an MBR to the disk.
It might be a good idea to explain what you did in more detail though if you need more concrete help,like how many disks do you have where do you have what installed which method did you use and so on.