Hello everyone I downloaded the Ubuntu Linux OS from their site.
and burned the .ISO to my USB and made it bootable etc. using UltraISO well I put the usb on my computer my computer currently does not have an OS
Well I'm installing ubuntu but theres a problem I'm at the "Prepare partitions" screen and It has the following

Device Type Mount Format? Size Used

I'm guessing this is where you choose to install the OS?
well the problem is nothing shows up it's all blank!
and it the bottom it has the following buttons

"Quit" "Back" "Forward"

When I click Forward it gives me the error
"No root file system is defined. Please correct this from the partitioning menu."

I don't know what to do.
Anyone help? =(

Edit:
When I click Quit installation It takes me to the ubuntu start up.
But I think t runs off my USB.

Seems it is not seeing your harddisk. What sort of hardware are you using?

Evo2.

Well It's a desktop.
Running the installation of the USB.

I was more thinking along the lines of your harddisk (IDE,SATA, etc) and perhaps motherboard.

Evo2.

Heres the type of computer I have
http://reviews.cnet.com/desktops/hp-...-30969217.html
But it currently does not have an OS the HardDrive messed up or something.

Are you saying that there is a physical problem with the harddrive? If so that would be why the Ubuntu installer does not see it. Can you remove the harddrive and replace it with a different one?

Evo2.

Boot to the BOIS and 'see' what devices your hardware 'Sees'