???That one was a shooting qn
The thing is that this is what I think you can do.It can by chance do some screwing if that is how it operates.
An alternative solution to that is to use bootable floppy with the format command and other commands that you need e.g Fdisk.
Before formating C ensure that you have only one hdd connected to your data bus(the one you want to format) then proceed with the format.When you are done then reconnect the hdd-1 and assign the later you want to the other hdd which you have just formatted.
I think this will help just a bit.