The USB was created without a single error, yet the PC boots straight into the old Windows - or never shows the stick at all. Nine times out of ten the media is fine and the handover is failing. This page checks the handover, step by step.
Keep one fact in front of you: Rufus finishing without errors means the stick is almost certainly good. Booting is a conversation between the stick and the PC's firmware, and every fix below is about that conversation - the menu, the mode, and the few seconds where your key press matters.
Changing the permanent boot order in firmware setup works, but the one-time boot menu is faster and changes nothing permanently. Restart the PC and tap the menu key during the first seconds - commonly F12 on Dell and many Lenovo machines, F9 on HP, Esc or F8 on Asus, F11 on MSI. The key varies by brand and model, so watch the first screen or check the PC's manual. If Windows starts loading, you were too slow - restart and start tapping earlier.
A GPT stick appears as an entry beginning with UEFI: - choose that one. If your stick appears only as a plain entry with no UEFI prefix and selecting it fails or loops, the PC is offering it in legacy mode: either the stick was made as MBR and that is correct for this PC, or the modes are mismatched. The scheme rules and the quick msinfo32 check are covered in our GPT or MBR guide.
Windows media often asks Press any key to boot from USB and waits only a few seconds. Miss it and the PC boots the existing Windows, which looks exactly like 'the USB does not work'. Stay at the keyboard on the first boot and press a key the moment the line appears. If the line never appears at all, the firmware is not handing over to the stick - go back to the boot menu checks.
For standard Windows media made by Rufus, Secure Boot can stay on - the Windows bootloader is Microsoft-signed, and Rufus's UEFI:NTFS loader is signed for Secure Boot as well. Where Secure Boot does stop you is with some Linux and utility images whose bootloaders it does not trust: the firmware shows a security violation and refuses. That is the firmware doing its job. If you consciously disable Secure Boot for such an image, note the change and re-enable it after the install.
CSM (Compatibility Support Module) lets a UEFI board pretend to be an old BIOS so MBR media can boot. It works, but be clear about the trade: enabling CSM can switch off features the board ties to pure UEFI mode, and it can confuse the boot mode of the Windows you are about to install. The cleaner fix for a GPT stick on a UEFI PC is almost never CSM - it is selecting the UEFI entry, or remaking the stick in the scheme the PC actually uses.
The video completes the picture - from a finished Rufus drive to the Windows Setup screen appearing.
▶️ Watch Full VideoWork the physical layer first: a different port (USB 2.0 at the back on old desktops), the stick reseated, other USB storage removed, and Fast Boot disabled in firmware so USB devices get initialised. If another PC sees and boots the same stick, the media is proven good and the problem is this PC's firmware settings.
Perfectly normal, and it usually means a mode mismatch on the second PC - a GPT stick offered only a legacy path, or Secure Boot rejecting a utility image. The stick is one fixed thing; each PC's firmware settings differ. Match the scheme to the stubborn PC or adjust its firmware consciously.
Not necessarily. Slow sticks can sit on a black screen for half a minute while setup loads. Give it a full minute once. If it never moves, test the media (checksum and a different port), then check the scheme match - a black screen is also how a wrong-mode boot often ends.