Probably the easiest is to use a Windows 98 Boot Disc and use the F Disc Function to remove existing Partitions and reformat after adding Partitions that you want.
But depending on where the Old HDD came from I personally Prefer to wipe the drive destroying all existing data and then treat it like a New HDD.
There are numerous Wiping Utilities available free but I prefer Boot & Nuke which is what I use when there is no Floppy available.
While Wiping the drives isn’t the fastest way to go about this you are at least sure that all existing Data is destroyed so none of it can come through and damage your existing install. I had a couple of End Users insert Old HDD’s into systems and destroy their OS because the Old Drives had Virus on them, and not wiping them saved them a few minutes.
If you perform a Format from either DOS or Windows this only writes to every third Sector so there is 66% of the old Partition available to transfered problems across. Not a problem with [b]Your Data[/b] but if there was an nasty infection on the drive it can be a major problem particularly if you don’t backup your Data as you can loose everything.
Of course you can always use the OS to format from all you need do is Open Drive Management in Windows and right click on the Drive and chose the Format Option.
It really depends on what you want to do and how secure you want to remain.