Back up and reinstall Windows on your main PC

You need this if Windows started on your main PC with an unflashed card in it. Windows logs the device it finds, and we can't be sure that record ever gets fully cleaned up, so reinstalling Windows is the honest fix. Tell us in your ticket that it happened before you start. Reinstalling for another reason, with a flashed card? Reinstalling Windows is shorter.

A clean install deletes everything on the drive. Most of the work is saving what you want to keep.

First, the card

DO NOT boot into Windows with the card plugged in until it's flashed. That includes your old Windows, to back up. Pick one:

• Flash it first.
  Keep the main PC in the BIOS and flash your firmware from your second computer. Once the card is flashed, Windows can start with it in, so you can back up from your old Windows as normal. This is the easier way.
• Take it out.
  Shut down, unplug the main PC, touch bare metal on the case and take the card out. Put it back after the reinstall, and flash it before Windows starts again.

Back up

• Your files.
  Copy Desktop, Documents, Downloads, Pictures and any game saves that aren't in the cloud to a USB drive, an external drive or OneDrive.
• Your logins and keys.
  Make sure you can sign in to your browser, Discord and game launchers, and note any software license keys you'll need again.
• Your Windows license.
  Go to Settings, System, Activation (Windows 10: Settings, Update & Security, Activation). If it says Windows is activated with a digital license linked to your Microsoft account, Windows activates itself again once the new install goes online. Microsoft says you have to reinstall the same edition, Home or Pro, for that to work.
• Other drives.
  A clean install only touches the drive you pick, so your other drives keep their files. Back up anything on them you can't lose anyway, in case you pick the wrong one.

Make the USB stick

Do this on any working computer. Your second computer is fine.

Windows 10 has been out of support since October 14, 2025, so use Windows 11 if your main PC meets its requirements.

Install

• Start from the stick.
  Plug it into the main PC, turn it on and tap your board's boot menu key, which is in the BIOS guide. Pick the stick, and if it's listed twice, the entry with UEFI in its name.
• Product key.
  If you have a digital license, choose I don't have a product key. Then pick the edition you had before.
• Where to install.
  You'll see a list of drives and their partitions, the sections a drive is split into. Find the drive Windows is on by its size, delete every partition on that drive only, then select the unallocated space it leaves and continue. Deleting a partition on the wrong drive wipes that drive. If you're unsure which is which, stop and ask in your ticket.
• Let it run.
  It restarts a few times on its own. If it starts setup from the beginning again after a restart, take the stick out.
• Finish in Windows.
  Sign in, connect to the internet, check Activation again, run Windows Update, and install your graphics driver from NVIDIA, AMD or Intel.

What about Reset this PC?

Windows can also reinstall itself from Settings, System, Recovery, Reset this PC, with Remove everything. It rebuilds Windows, but Microsoft says it keeps the installed drivers and never formats the Windows drive. A clean install from the USB stick, with the old partitions deleted, starts from nothing. After an unflashed boot, use the USB stick.

Done

If you flashed first, carry on with second computer setup. If you took the card out, Main PC Setup covers fitting it again, and it gets flashed with the main PC in the BIOS before Windows starts.