Ill cut this short again. Okay, so, I was wondering about trying Ubuntu without installing so i tried. And then the PC boots elementaryOS, no isolinux.bin error which had happened before. I used Startup Disk Creator (installed via Terminal) to burn the iso file to the usb, seems like it worked. My question is, Does anyone know how to boot another OS via USB? elementaryOS is my primary system.
When booting up your system (be sure to plug in your ISO USB before booting) you should see a BIOS screen indicating what keyboard button to press to get into the Boot Options, in my case it's F12. From there you should be able to choose to boot into the USB Drive to run from the ISO & give Ubuntu a try. You may have to run your system setup from the BIOS screen (in my case it's F2) to change some settings if you don't see USB as a boot option. These keyboard shortcuts can vary based on computer & hardware manufacturer. I have another laptop that uses the ESC key & other keyboard shortcuts to access the BIOS. Let me know if this helps & if you need further guidance.