I'm rather new to Ubuntu and Linux in general, I've been using Windows for years and recently I got an old Dell that was running windows 2000 and I'm hoping to get Ubuntu installed.
Now, the BIOS is pretty old so it can't boot from USB and the disk drive is broken, no idea why, so I can't boot from externally. After searching around the internet, I found Unetbootin, was told that it can install Ubuntu on the computer that it's run from, great. Got that downloaded, selected an ISO for Ubuntu 12, 32 bit. After running the installer on windows, I rebooted the computer and booted from the Unetbootin option. Everything booted up nice, on the live session user and clicked the "Install Ubuntu 12.04.2 LST" icon. Everything was going good until I got to the Installation Type screen, none of the buttons work and the fields are all blank. There's a drop down button for "Device for boot loader installation: " but the only option I have is "/dev/sda".
I can press the Install Now button but it gives me the "No root file system is defined. Please correct this from the partitioning menu." error.
I've tried booting to Windows, re-installing Ubuntu through the Unetbootin program a few times but it doesn't seem to change anything. I want to completely wipe the computer and start fresh from Ubuntu, no dual OS's, just Ubuntu when I'm done, but I can't get past this point.
Is there something that I missed, another tool that I can use, anything?

Thanks!