Think the (5) Partition problem distracted everyone, including me, from your (real) issue. :( :(
Had to dig deeper by mind reading. (lol) (lol)
Read your Bios manual quickly.
I Remember when I experimented with Ubuntu, I had to set-up this Asus Board Bios settings differently.
You are going to have to play with your Bios Settings abit.
Try setting the Bios to Legacy Enabled.
Configure SATA as Standard IDE.
What you may see when menu is changed is something kinda like P-ATA + S-ATA OR some variation.
Read Both manuals completely.
The object is to get the SATA HDs set-up to act as IDE (ATA) HDs with NO Raid.
Sorry I can't help more as I can't put my hands on your keyboard and try settings.
It (CAN) be done as my old Asus Boards have similar Bios settings (maybe more) and I ran Ubuntu. :) :)
EDIT: Your HDs are SATA, the Jumper Settings are for Generation I and Generation II.
Set the jumpers for Generation II - (300) per HD manual and mother board specs.
Also ensure the cables are connected to Primary SATA Connectors.
Rick P.♦ :)