It's a shame we never got the requested Disk Management screenshot or confirmation that Windows 7 partition had been marked Active with Startup REpair run 3 separate times. We could have helped you fix this as we have countless others over the years.
When you kept reporting back that you were receiving BootManager Is Missing error, I kept asking you if you'd marked Windows 7 partition Active and run 3 startup repairs with the XP HD unplugged. You'd never clarify if you'd done this. Why ignore repeated requests and then take it to a shop? This is one of the easiest things we help to fix here.
If you don't want to do the work to repair it correctly, then don't just write off a perfectly good machine. Unplug one HD, wipe the other to Clean Reinstall - Factory OEM Windows 7.
Since you apparently didn't read these before, I'll put them here one last time so you can see exactly what was needed to get Windows 7 started:
1) unplug all other HD's.
2) Boot Windows 7 DVD or System Repair Disk
to Mark Win7 Partition Active.
3) then run Startup Repair - Run 3 Separate Times
. Yes, that says 3 separate times - not to run it once and ask back if you should run it two more times, then just ignore the reply.