Remove Windows 10 to leave no OS behind. How?

[The_Doc]

Parents computer needs to go back to supplier.

It came with no OS, I put Win10 on it (with purchased key)

It is going back and I want to revert to empty hardrive, remove Win10 OS. Then start afresh with a new box and no OS (and use initial key)

How, please?

[The_Jackal]

There will be a download for a usb drive, so you can boot from the usb drive and wipe the hard drive.
I used to use something called Hirens Boot CD, but there may be something simpler and more dedicated to just wiping a drive.
Just google how to wipe drive from USB.

[colin79666]

If it still boots, bitlocker the drive. Then boot from the win 10 install media, command prompt. Then
Diskpart
List disk
Select disk x where is is the drive number from list above
Clean

Then into bios and clear tpm.

That will remove the partitions etc and bitlocker first should ensure no data is recoverable.

If it has a hard drive not ssd then dban would likely do.

[sicarumba]

Could be worth freeing up the Windows 10 licence key before you do this, in the command prompt (run as Admin) type slmgr.vbs /upk

[The_Doc]

sicarumba said:

Could be worth freeing up the Windows 10 licence key before you do this, in the command prompt (run as Admin) type slmgr.vbs /upk

did this, very very useful.

The_Jackal said:

There will be a download for a usb drive, so you can boot from the usb drive and wipe the hard drive.

and then this.

All sorted, thank you guys.

[Duke of Kidderminster]

colin79666 said:

If it still boots, bitlocker the drive. Then boot from the win 10 install media, command prompt. Then
Diskpart
List disk
Select disk x where is is the drive number from list above
Clean

Then into bios and clear tpm.

That will remove the partitions etc and bitlocker first should ensure no data is recoverable.

If it has a hard drive not ssd then dban would likely do.

You could achieve all of this by just deleting the recovery key after encryption. No need to wipe the drives