Question Unable to format D:/ drive ??

Jul 2, 2019
3
0
10
Hi there, I'm selling my computer on gumtree however I ran into a problem, currently run an SSD which contains all the windows files and is the one I boot up from and I have a secondary drive I use for storage but this also has windows on it, what i want to do is format the secondary drive but for some reason windows will not let me format it, and when I go into disk management its the same problem , and for some reason it lists my secondary drive as disk 0 and my C drive as disk 1? Will I need to rearrange these for windows to allow me to format my D Drive?

Any help would be greatly appreciated, thanks.