Once you have a bootable USB drive ready and your PC set to boot from it (see our dedicated USB boot guide if you haven't done that part yet), the on-screen installer itself looks nearly identical across Windows 7, 8.1, and 10 — the same core screens, in the same order, with only minor cosmetic differences between versions.
Before You Start
- A bootable USB drive already prepared with your Windows installation media
- The PC already configured to boot from that USB drive
- Your product key, or a plan to activate after installation
- A backup of anything on the target drive, if doing a clean install
1.Boot into Windows Setup
With the USB drive plugged in, restart the PC and boot from it via your boot menu. See our dedicated USB boot guide for the exact key combination if you're not sure which one your PC uses.
2.Choose language and click Install now
Select your language, time/currency format, and keyboard layout on the first screen, then click Install now to begin.
3.Enter your product key
Type in your 25-character key when prompted. You can also select "I don't have a product key" (Windows 10) or use a matching generic setup key (older versions) and activate properly after installation instead.
4.Accept the license terms
Check the box agreeing to the Microsoft Software License Terms and click Next to continue.
5.Select installation type
Choose Custom: Install Windows only (advanced) for a clean install onto a reformatted drive.
On Windows 7/8.1, an "Upgrade" option is also available, but only when Setup is launched from within the currently running OS rather than booted from USB — booting from USB always performs a custom/clean installation path.
6.Prepare the target drive
Select the drive/partition you're installing onto. For a genuinely clean install, delete existing partitions first so only unallocated space remains, then select it and click Next.
Setup automatically creates the partitions Windows needs and begins copying files — this stage typically takes 10–20 minutes.
7.Complete the out-of-box setup
The PC restarts automatically several times while Setup finishes copying files and configuring the installation.
Once at the out-of-box experience, follow the prompts for region, keyboard layout, network connection, and account setup (Microsoft account or local account, depending on version and your preference) to reach the desktop.
Confirm the install and activation
Once at the desktop, check activation status — Settings > Update & Security > Activation on Windows 10, or System Properties on Windows 7/8.1. If you skipped the key during Setup, enter it now from there.
Troubleshooting
| Issue | Likely Cause | Fix |
|---|---|---|
| Setup shows "Windows cannot be installed to this disk" | The drive's partition table type (MBR vs GPT) doesn't match the boot mode (Legacy vs UEFI) the USB drive was created for. | Delete all partitions on the target drive so Setup can recreate them fresh, or switch the boot mode in BIOS/UEFI to match how the installation media was built. |
| Setup freezes at "Getting ready" or "Getting devices ready" | Often a slow or failing USB drive, or occasionally a network adapter driver issue. | Give it 15–20 minutes before assuming it's stuck — this stage is genuinely slow on some hardware. If it's still frozen well beyond that, try a different, faster USB drive or port. |
| No product key prompt appears at all | Some OEM recovery media pre-fills the key from firmware automatically. | This is expected behavior on OEM systems — check activation status after install rather than looking for a key prompt during Setup. |
