Quick easy way to format the HD and erase all files?

I went back to the Amazon sale page and found this:

When you purchase the computer it comes with a free upgrade to Windows 10. When you start up the computer you will be prompted for the upgrade. If for some strange reason you are not prompted for the upgrade all Windows 8 users are entitled to a free upgrade, So you can go to Download Windows 10 and download the "media creation tool" and follow the prompts to install.

Looks like it's installing 10 now....

It crashed & shut down. Did a scan when I restarted. Now it says I still have an 8.1 PC and keeps shutting down when I try again.

Hi MamaBear

If the PC in question is the one in the first post, you could get the Windows 8.1 iso image from MS, use a tool like RUFUS to create a bootable USB drive, and reinstall 8.1 fresh, using a generic name like User for the admin account. During a fresh install you're given the opportunity to delete all partitions on the drive if it has partitions, as is your case... delete the existing partitions from the last one to the first - recovery, efi, then boot, etc. Install fresh to a Drive 0 with the unallocated space = to free space = 250GB unallocated = 250GB free space. This will remove all your data and will give the new owner an opportunity to do as they see fit with a fresh Windows 8.1 install. You might also install the requisite software - audio, video, networking, storage, etc from the OEM's site to save the new owner time. The product key is embedded in the BIOS and is tied to the PC. The OS should be activated, if not, it can be quickly done online.

BTW, in-place upgrades usually have some sort of problem, I would do a clean install of 10 if possible... I know that in some cases a user wants all the old apps and any files generated with em... an upgrade is the way to go in this case. I usually prefer to install a new drive and install fresh to it... pop the old drive out and store it away.