I'm no expert on Ubuntu but have over 20 years experience troubleshooting radios on aircraft. From a troubleshooting perspective you have a lot of unknown variables happening at the same time.
You may want to make sure the hardware is working before going any further. This can take some time but may save considerable time and frustration in the long run. It will also give you a known state from which you can add changes incrementally. In good troubleshooting, unless you are confident of the root cause of the problem, you only change one variable at a time.
Will the computer start with original OS? If not I would probably reload the original OS as a starting point. You may even want to reformat the hard drive, then reload original OS. I assume data loss is not a concern.
If you don't want to install or run the original OS, you may want to format the drive then try loading a particular Linux flavor. This will at least give you a known state as a starting point.