You might be better served by starting over with a 'fresh' VM. Download RPetruska's VMX builder and create a new machine. Then, boot into that machine with a floppy and FDISK and FORMAT as Kevin suggested. Just remember, a virtual machine behaves exactly like a physical machine. If you can keep that in mind most problems you come across will be easier to solve, i.e. having to FDISK and FORMAT a virtual hard drive. If you had a newly built PC and a new harddrive in it. You would have to FDISK and FORMAT the drive in order to use it(Or have a bootable CD for an OS that would do it for you).
Good Luck!
