Save my unbootable Windows installation using Windows on external HDD?

A power failure during a Windows Update left my computer unable to boot. I have tried many things including System Restore, Automatic Repair and even Recovery to no avail. I've been able to gain access to the hard drive by installing windows on an external HD and plugging it into the computer.

Now that i'm in there, is there a way I can salvage the OS on the main HDD? And how would i go about doing that? I would prefer not doing a complete wipe and install. I tried installing and keeping my files through the recovery console. That didnt work.

Thanks for your response. My hard drive is fine. I have also updated my specs. I followed the instructions on that page. It found some errors and fixed them but I am still unable to boot. Startup Repair no longer finds any errors. If I try to do an install from the recovery console, it doesn't complete and I am still unable to boot. I get the windows animation and then "Set up is starting services." I then get an error saying"

"The computer restarted unexpectedly or encountered an unexpected error. Windows installation cannot proceed. To install Windows, click OK to restart the computer, and then restart the installation."

A restart puts me at the same screen.

If you've tried everything in Troubleshooting Windows 7 Failure to Start to no avail, have rescued any files using the tools provided there and are ready to give up and reinstall, then follow these toubleshooting steps:

Unplug all other HD's and peripherals,

Boot into BIOS setup, reset to defaults, save changes. If an EFI BIOS you'll need to decide if you want UEFI BIOS vs. Legacy BIOS. If UEFI follow these special steps for Install, otherwise enable Legacy BIOS or Compatibility Support Module to proceed with normal install:

Set DVD drive first to boot, HD second, set SATA controller to AHCI, Save changes and Exit.

Then boot into Windows 7 installer DVD or flash stick burned or written using tool and latest ISO for your licensed OS version here. I would use a fresh ISO written with tool in Step 2 as yours is in question.

At first installer screen Press Shift + F10, or enter System Recovery Options to open a Command Box, type:

DISKPART
LIST DISK
SELECT DISK 0 (after confirming Windows 7 target HD #)
CLEAN
CREATE PARTITION PRIMARY
FORMAT FS=NTFS LABEL="WINDOWS 7"
ACTIVE
EXIT
EXIT

Next click Install Now, then Custom install to Clean Install Windows 7 to the partition you created. If it fails then report back at which step and the verbatim error message.

In addition read over these steps to understand the tools and methods which work best to get and maintain a perfect Clean Reinstall - Factory OEM Windows 7. The steps are the same for retail.

After install you can adjust partition size or Create new partitions for data, etc. in Disk Mgmt. You are creating the partition here for the purpose of wiping the HD and marking Active which overcomes certain install failures.

I was hoping I didn't have to give up yet. One more question. If I back up the "User" file from this computer, can I reinstate it after I do a clean wipe?

Thank you so much. I'll do that then do a clean install.

eMachine said:

I was hoping I didn't have to give up yet. One more question. If I back up the "User" file from this computer, can I reinstate it after I do a clean wipe?

You can do that but I wouldn't reimport the hidden User Appdata files because those settings are a corruption path back into a fresh install. So you really only need the active User folders if you've sorted all of your files into them, plus any loose files you have. In addition everything else which might need to be saved is gone over in Clean Reinstall - Factory OEM Windows 7 . It also tells you how to rescue files if you can't boot the OS.