ubuntu is not finding hard disks and partition table is empty

I am trying do a dual boot installation of ubuntu using usb and when I go to install, the partition table is empty. When I then ran
sudo dmraid -Er /dev/sda
it said that there were no block devices found. When I ran gparted, the only device that it recognized was the usb itself, but not the hard disk.
How should I go about this?
thank you for your time

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