Unable to format my win10 PC

Hello,

after much fought I decided to move away from windows 10  and go back my windows 7.
In the past I always used  Darik’s Boot and Nuke (DBAN) tool to wipe everything out,
it was recommended on this forum and I have always been very happy, to note that I always used on win7

Now I try to do the same thing on win10 but it does not work, the tool seems to do the initial thing
but than I get a page that tells me that he does not recognise any of the drives... I only have one.

I even tried to install win 7 using the cd without a full wipe, but at the page where it asks where do I
want to install windows, it gives me four options (looks 4 four partitions of the same drive) but I cannot choose any of them.

Any idea of what I can do?

Thanks

by basic formatting, do you mean at the cmd prompt?

OK, I will try the last suggestion, and than try dban again from win7.

I did try to boot from win7 cd, but it did not ask me to format, or it did not get to that part.

When I use Dban I always boot form it, that is the only way I know how to :-)

OK, after playing with EaseUS Partition Master, I was able to make the PC install Windows 7 on the main partition,
Honestly I am not sure what I did, I delete some small partitions and at the end he accepted to instal win7 on the main partition.

I can see that I still have a windows.old forlder of 151GB
and I am not confident that a good clean up was actually done.

So I decided to boot from DBAN now, hoping that with the change it would work,
but I still get the same issue as before
I get presentaed with the window as following:
[?] Unregognized Device
[?] Unregognized Device
[?] Unregognized Device
[?] Unregognized Device
[?] Unregognized Device

It looks like there is a line for each partition but I cannot select anything.

While I was waiting for the answer, I did something very bad...
I deleted all partitions and than rebooted with Windows DVD
I was able to install Windows and than use DBAN
I now also re-installed again Windows and I have a beautiful clean and single drive with only 21 GB used
which I assume it belongs to windows install and various system requirements.

It is so nice to have a clean computer... for 10 minutes, because I am already busy installing other stuff now :-(

Thanks so much as always

It was an option when I booted form the Windows DVD,
I got to the window where asked me where I wanted to install Windows, but somehow
again it did not let me choose any of the partitions due to their type, I was there where
I selected to delete everything. The system than rebooted and picked up the DVD again
I did a new installation again and finally I rebooted from DBAN and it worked :-)

Serious...

Congrats on winning through sheer will. I was going to suggest that you delete the partitions, just like you did. But I was busy at work and did not get the chance. By the time I got home I was wiped, just like your partitions.