I originally posted my problem in the German language forum accidentally. I did not notice there were two sections.
I installed Univention Corporate Server and it went as good as can be. Upon reboot it states: "Reboot and Select proper Boot Device[...]"
There is only one possible boot device in there, the hard drive UCS was installed on. The hard drive is used, and a seagate, so it could be bad. I am not a Linux person (yet) so I am not certain how to proceed. I can load the installation USB and tell it to "Boot from first hard drive", but that leads to more errors. Such as---Okay now it won't even generate the errors. It just beeps and comes back to the main menu.
Another poster suggested using a different hard drive, since a defective HD could be the culprit. So I used a brand new one...same result.
If I load the installation media and select "boot from first hard drive" it goes straight into Rescue Mode asking me for my language.
So,I burned a disc of UCS, instead of a USB drive, loaded it successfully, selected Load First Hard Drive,and it says... "Booting..."
Just "Booting...". It does not get past "Booting..."
I am performing another install on different hardware. Who knows, it could have been that Gateway desktop. Hopefully it works fine this time...