I installed linux mint 20.1 mate and am having boot error issues and it is conflicting with the software I'm running. Want to uninstall 20.1 and install 19.3 mate. This is not a dual operating system. I have created a usb install disk of 19.3 and tried to boot over the 20.1 with the usb. I get a blinking cursor for a second followed by a very quick error msg and then it goes to a blank screen. There is nothing on this computer I need to keep. Using it for an ar sandbox and starting fresh would be easiest for me. Please help!