Yes, of course. If your drives are named C and D, and Windows is installed on your C drive then you can format your D drive from Windows -> right click the D drive in Windows Explorer and choose format from the pop-up menu.

If Windows is installed on the same drive that you wish to format then you have to do that from a DOS prompt -> type format C: (of C is the drive) and press ENTER.

WARNING - formatting a hard drive will delete all your files and programs!!!!

Hope that helps
THT