BootMGR and NTLdr issue with multiple drives

I had a smaller WinXP drive in the computer running fine. I installed a newer, larger drive and successfully installed Win 8.1 on it. Ran for about a month with dual boot option. Decided I've gotten everything migrated so used Active Killdisk to erase everything off the XP drive. Apparently, that also removed the boot record for both drives (according to: Startup Repair - Run 3 Separate Times - Windows 7 Help Forums).

So now I'm stuck with an installation that won't boot into Windows. I've read different ideas, tried using diskpart, diskmgr, bootrec, installation disk, freeware, but no dice. Any suggestions appreciated.

Thanks

So running Startup Repair 3 times did not make any difference?

I wonder if the partition is set as Active? All the files may be there now but if it's not Active it won't boot. You can do this from the install DVD Command Prompt using the diskpart command.

See here: Partition - Mark as Active - Windows 7 Help Forums

Says it's for Windows 7 but works for Windows 8 as well.

Running startup repair did not make any difference. I'm looking at the volumes and partitions now in DISKPART and making sure the correct ones are marked as active. Running Bootrec/RebuildBcd finds the installation of Windows, but says "The volume does not contain a recognized file system". Ditto error message for Bootrec /Fixboot. Bcdboot c:\windows /l en-us results in error message "Failure when attempting to copy boot files." I'm going to once again ascertain the correct active volume and partition then try Startup Repair 3x again.

and if after 3x of Startup Repair, it still says it can't fix things, that means you are still looking for a solution, right?

Suggestions appreciated here!

What does diskpart, list disk and list vol show?

the List Disk and List Volume commands in DISKPART show the correct disk, volume, partition and were set as active.

Well, I don't know why my computer decided to start working now, but it has. Steps I took in order this time to resolve the issue:
Boot with the install disk and choose repair option
Get to command prompt
Change to c:\windows
Diskpart
List disk, list volume, select volume, mark active, list partition, select partition, mark active
exit Diskpart
Bootrec /ScanOS (and it found the windows installation)
Bootrec /FixMbr
Bootrec /FixBoot (and those were successful this time - who knows why)
exit and restart
Windows recognized that there was a problem with the Boot Record and told me to reboot and choose the "fix startup problems" from the installation CD.
Did that, restarted and all is normal.

Thanks to all who contributed the help on this thread.

Sure would be nice to know what fixed it but hey, success is great! Glad you are back working again.