New to Linux.
I put Ubuntu on my USB stick; installed Ubuntu while removing Windows 10. Currently on single-boot Ubuntu, but it's crashing very often not long after startup, requiring full reboot each time. I'm not sure what's causing the constant crashing. I think it may be that I configured the bootable USB wrong. So I wiped by USB and configured it again with UNetbootin. So I want to reinstall Ubuntu, but I'm stuck as to how. When I configure my BIOS to boot my from USB, it just skips the USB and goes to the next in queue (e.g. my current Ubuntu OS).
How do I start a fresh installation of Ubuntu on my computer? (No need to worry about backing up files, the few that I need are on an external harddrive.)