Format old SSD with Windows 10

Hi All....
I recently upgraded to a PCI SSD and want to format the SSD with the old installation files on it and use it for storage. What would be the proper way to go about this with both versions on those drives being Windows 10, and the new PCI SSD Windows 10 Creators Update? I tried to format the drive, making sure nothing is on there that I want, and I get the message that it is in use by another program. The only thing that I could think that might be accessing it is Carbonite, and I paused that while I was trying to format it. I even tried going a little more brutal on it, and doing it with the Cmd Prompt, and runing DISKPART> clean and Format fs=NTFS.... and I get "Virtual Disk Service Error" Clean is not allowed on the disk containing the current boot, system, pagefile, crashdump or hibernation volume." I also tried Disk Management, and the option is there, but greyed out.



Any suggestions? I'm sure this can be done, there's just a proper way to it since it has an old boot file on it. I'm hoping I don't have to boot to it and do it that way. I'd rather stay out of BIOS if I can.

What kinda of changes would I need to make? I

If I remember correctly, the OS ended up becoming corrupt and wouldn't boot anyways. So it was a clean install on the PCI SSD

I confirmed by unplugging the 3 other SSD's that the system still boots. So, nothing is "tied" to that particular SSD

Copy that. I know I tried this method, just, not selecting the exact partition of the OS

The command after selecting the partition should have been delete part override. Not clean override.

So... I was able to chip away the partitions. There were 3. I can't seem to get rid of the last one tho.