I have my HDD 1Tb partitioned with fs ext4. Previously I was booting from the 2TB Hard Drive...I disconnected that. Now I want a clean install 12.04 but cannot figure out "Root File System" ("/") Crazy...had the same problem 2 years ago...two weeks then...I should have written down the answer! Can anyone help an old man? Thanks
I assume you are using the manual partitioning option - something else I think it is called.
Select the partition you want to install in - Edit - in new window select / from the dropdown - format as you wish.
Exit that back to the partition list.