External HD like Shautieh said, come from factory with FAT32 for compability.
So all you need to do, is reformat with NTFS (or convert, but I wouldn't take this route.)
Just a reminder, if you do format/convert to NTFS, you will lose the ability for that hard drive to be read on MAC,LINUX*,Windows ME or lower
*Without a NTFS Kernel Driver.
Now if you want to format (You will lose any data on the HD! backup it first)
Plug the HD, right click on it from My computer.
From this simplistic screen, look at the size check if is the correct one.
File system: choose NTFS.
Allocation: Don't touch.
Volume Label: Name your HD as you please, or leave blank.
Checkboxes: leave all unchecked.
Start, sit back wait for it..
"Chile is a thin and tall country"