Windows 10: Win 7 install after hard drive

My Dell Desktop PC came with Win 10. I hate Win 10, Could not duel boot with Win 7 so I debaned HD and tried to install Win 7. Would not install. Kept getting notice “Setup does not support configuration of or installation top disks connected through a USB or IEEE 1394 port.” I'm using an authentic Windows Win 7 installation disk. However, I was able to load Linux Mint, OS.sort of. I also tried to re-install Win 10..that did not work either...PS: is UEFI the problem?

:)

 

Hard drive/ OS issue

a guy suggested :

• shutdown
• unhooked HDD
• restarted
• yay !!
• reconnected HDD
• restarted
• yay !!

also , try method 3
How to Unlock Drive in Windows 10: 5 Ways to Remove a Lock

 

Installing windows from usb hard drive

So how did you set up Win 7 to install from a USB hard drive?

 

Error Message when updating from Win-7 to Won-10

Bree
I followed your suggestions (2nd Aug 19) for installing Win-10. Made the bootable flash drive successfully through the media creation tool. But when I attempted to upgrade and activate to Win-10 (64 bit) from within Win-7 (Pro-32 bit), I got the following error message:

Error # OxC1900101-Ox20017. " The installation failed in the SAFE_OS phase with an error during BOOT operation"

I read the diagnostics under this error number and carried out the proposed fixes, i.e. update Win-7, uninstall Malwarebyte antivirus, disconnect all external hardware, e.g. printer, scanner, external hard drives. I then tried to repeat the steps to do the upgrade through the Win-10 bootable flash drive as before. Got the same error message.
Appreciate any further comments and suggestions as to (a) what does a failure in the SAFE_OS during boot operation mean, (b) what can I do to solve it. Is this anything to do with the hardware in my computer? I listed these in my first posting above.
Thanks for any help