I was having the same problem and this is what helped me.
problem 1. from "bootrec error - element not found" to "bootmgr is missing"
I made progress but still not there yet. **In diskpart i used select part and then made partition active.**Then rebooted and now it says something new "bootmgr is missing." I used the win7 disk and now it does find my win7 installation. It still does not boot but progress has been made nonetheless.
problem 2. from "bootmgr is missing" to "problem solved"
Using win7 disk to get to cmd prompt I typed bcdboot C:\windows /l en-us "enter" and that fixed or replaced bootmgr.
Problem solved!!! Booted into windows and everything is fine!