Go to disk management, right click on computer and select manage then in the next window select disk management and in the next window you will see all the drives that are connected to your computer. Right click on the old hard drive and select delete partition, that will make the hard drive a raw status and you can now create a new partition and format it and give it a drive letter and it's done.
Could be wrong. But i believe where your running into an issue is it's a *system* partition. So it's not allowing you to format from there trying to prevent you from messing up an os. Unplug your ssd. (as to not accidentally format it) Boot to your windows disk format the drive and be done (prolly be a good idea to unplug your other drivers u have on there too so you make sure u get the right one.)
That OR could be that you need to be opening computer management as an administrator.
Hope it helps. But inzone was correct that's the best / easiest way to go about it.
thanks for your input guys but i fixed it my hdd was still disk 0 when i swapped the plugs around and made the ssd disk 0 it made it the system drive and i was able to delete the old partition and make a new one