I am trying to re-install Ubuntu as it just isn't loading up well at all. However, I am getting this error:
You need at least 8.5GB disk space to install Ubuntu. This computer has only 4.0GB!?
- How can I partition the hard drive to make this work?!

Update: I opened GParted to start partitioning my hard drive but this was my only option.

I have a terrabyte on this computer, why aren't the other ones showing up?
I was advised to go into terminal and to type DF. You can see the results below:
Just to confirm that it isn't recognizing my sda: