Check BIOS/UEFI settings. Disable Secure Boot temporarily if needed (Ubuntu supports it, but some hardware is picky). Also, try a different USB port (preferably USB 2.0).
Download (free, reliable):
✅ Download the latest LTS version (currently Ubuntu 24.04 LTS "Noble Numbat"). ubuntu linux iso
Yes, but it’s more complex. Methods include network boot (PXE) or virtual machines. For beginners, USB is strongly recommended. Check BIOS/UEFI settings