You ok connecting them to pc/laptop? You can either do this by external hard drive caddy, or connect them internally to a spare sata/pata port and power supply.
If so, connect them up, in windows goto file explorer, right click on the drive you want to format, select format, then you can specify ntfs or fat32 if you want, done. simples.
If you want to be extra safe, then download a program called ccleaner, on there it has an option to do secure erase with up to 7 passes.
You'll be able to do the one that windows isn't loaded on, but not the windows one, you'll have to do that on another pc.
Edit: unless you have a windows install disk. If you do, once you've formatted the storage drive, then boot into the windows install disk and the first stage is managing disk partitions, there you can choose to format the windows partition and then once complete, exit the install.
Its effectively a partitioning programme that is essentially in its own operating system that will run on a memory stick or CD/DVD. From there you can properly format all of the drives within the system with no problem. No need for another PC.