Solved After a failed Windows 8 installation, I can't boot into Windows 7

[SevenDeri]

Can't boot into Windows 7 after a failed Windows 8 installation.
One day, I tried to install Windows 8 on my Sony VAIO VGR-A600. The installation failed, and the computer rebooted and showed me an error in the Windows Boot Manager.

File: \$WINDOWS.~BT\Windows\system32\winload.exe

Status: 0xc0000428

Info: The digital signature for this file couldn't be verified.

Then, I press Enter to go back to OS Selection, and I see two options. Windows Setup or Windows 7. If I click Windows Setup I get the error mentioned above. If I click Windows 7 it takes me straight to the System Recovery Options. Startup Repair doesn't work, System Restore doesn't work, I can't use System Image Recovery, and Command Prompt works. I checked and it says my HDD and RAM is fine. I just can't get passed the Windows Boot Manager.

 

[gregrocker]

Do you know for sure you attempted to install Win8 in a Dual Boot configuration to its own separate partition and were careful not to overwrite the Win7 installation? If so then Mark Win7 Partition Active and then run Startup Repair - Run up to 3 Separate Times from the booted Win7 installer or System Repair Disk Command Line - if you need a Win7 installer it will be provided in the next paragraph.

However if you were careless and didn't plan or pay attention to where you installed Win8 then you have no reason to believe Win7 still exists and should skip to the step to Clean Reinstall your licensed version provided in step 1. The steps given will assure you get a perfect install, likely better than the one you had before so stick closely with them.

During booted Custom install delete all partitions and create and Format New using the Drive Options shown in Step 7 of Clean Install Windows 7 .

 

[SevenDeri]

Do you know for sure you attempted to install Win8 in a Dual Boot configuration to its own separate partition and were careful not to overwrite the Win7 installation? If so then Mark Win7 Partition Active and then run Startup Repair - Run up to 3 Separate Times from the booted Win7 installer or System Repair Disk Command Line - if you need a Win7 installer it will be provided in the next paragraph.

However if you were careless and didn't plan or pay attention to where you installed Win8 then you have no reason to believe Win7 still exists and should skip to the step to Clean Reinstall your licensed version provided in step 1. The steps given will assure you get a perfect install, likely better than the one you had before so stick closely with them.

During booted Custom install delete all partitions and create and Format New using the Drive Options shown in Step 7 of Clean Install Windows 7 .

Unfortunately, I tried to install Windows 8 over Windows 7, and got this error.

 

[gregrocker]

Let us know how the Reinstall goes.

If it balks you may need to wipe the HD first or even define an Active partition from SSD - HDD Optimize for Windows Reinstallation

 

[theog]

To go back to Windows 7 run the backup you made before upgrading to Windows 8.

Upgrade to Windows 8 with only a product key - Microsoft Windows

• Make sure you’re on the PC you want to upgrade. This must be a PC that is currently running Windows 7, Windows Vista, Windows XP with Service Pack 3 (SP3), Windows 8 Release Preview, Windows 8 Consumer Preview, or Windows Developer Preview. (Windows 8 Setup checks that your PC meets all system requirements before it installs Windows 8.)

• Have your product key handy. You can find it in your online order information, in the confirmation email for your purchase, or on the packaging. The product key will look something like this:
XXXXX- XXXXX- XXXXX- XXXXX- XXXXX

• Make a backup of everything you want to keep. Save it somewhere you can get to it later, like an external drive or a DVD.