How to format hard drive
If the drive you want to format is also the drive you are using, you cannot change the format. Easiest way is to use a Live Boot disc and boot up inside the Trial area (where it gives you the option to install Ubuntu on the desktop). From there, you can format the drive, but be aware that formatting will erase data from the drive.
Use Gparted, burn it to disk,and boot the disk and format, you cannot format while working on Ubuntu, the hard disk is mounted