Running Windows 10 Pro, unable to reinstall Windows 7 Pro

[Puttsboy66]

My computer is an HP Pavilion 500-205t DT, I was running W7 Pro and when W10 became available I downloaded it to a USB. I installed W10 Pro and it functions normally and my other applications work well within W10 Pro. I like W10 however, I would like to go back to W7 Pro. I have installed OS's over the years many times without any issues. I have 3 types of media to install W7 Pro, dvd, usb and a set of factory reinstall disks. I have tried all three media trying to reinstall W7 Pro and each time near the end of the installation I receive the following error message: The computer restarted unexpectedly or encountered an unexpected error. Windows installation cannot proceed. To install windows click ok to restart the computer, then restart the installation. This event happened while trying to reinstall (clean) W7 Pro. I have tried suggestion to edit the registry to look for the childcompletion setting, but am unable to get to the registry editor from the error screen. The installation media works fine on my Compaq Presario. I would appreciate any help in this matter. Thanks for reading my post.

Additional Information: during the boot in Windows 10 the computer shows an HP Logo. Then the W10 startup screen, which it never did when running Windows 7. Also the "click ok message" would appear when the: Setup is preparing your computer for first time use screen. When I look at the boot sequence it shows a group, "Legacy Boot Sources" that's where the hard drive (SATA0) is located. I'm open to suggestions provided they come with explicit instructions. I'm eager to learn. Thanks to everyone.

 

[AddRAM]

Set the bios to defaults and/or make sure Secureboot is disabled.

Try again.

 

[ThrashZone]

Hi and welcome to SevenForums,
Also if win-10 will still start as it did before make sure you disable fast start in win-10
Fast start is a well known feature of win-8 which is real referred to as Fake shutdown using more or less hibernation mode and not full shutdown
One you disable fast start use Winky+X and Power and shutdown from there
You can also right click the start button for the power listing it more reliable than the start menus power listing.

Also turn fast start off in your bios too.
Fast Startup - Turn On or Off in Windows 10 - Windows 10 Forums