I want to completely wipe my external hard drive for time machine...

but when I click 'erase', it asks me to create a password for the partition. I don't want to create a password OR a partition, I just want a single, whole partition on an external hard drive.

The reason I wanted to do this in the first place was because when I eject my hard drive, it asks if I want to eject both partitions or just one... I don't remember ever creating 2 partitions :s

How can I just wipe the hard drive to, kind of, start over again?

Disk Utilities (Applications > Utilities)

Launch the app and select your ext disk on the left

Select the partition tab and select one partition and format it as Mac OS Extended and hit the partition button