I tried to install Ubuntu on a dell vostro 5581 computer. I followed the same directions used to install it on my Inspiron. It would not install. I went into the bios and attempted to get it to install in legacy boot mode. In the process, I accidentally removed windows boot loader. I performed a BIOS Flash update thinking that this would get the correct tools needed for an install, but it didn't. 

 

With the Ubuntu USB stick removed after attempting several installs, I get these messages when starting (without F12) the message PXE-E61: Media Test Failure, check cable and PXE-MOF: Exiting PXE Rom. No Boot Device Found.

Essentially, I can get the computer to run Ubuntu from the usb stick, and "installed", but it will not boot from the internal hard drive. Any ideas would be helpful!