Quick Answer

download the official Windows 10 ISO from Microsoft, write it to USB with Rufus, install (skip the key), then activate with your Windows 10 Pro key. Windows 10 left standard support in October 2025 – security coverage now runs through the ESU program, so plan your Windows 11 path alongside.

People still install Windows 10 Pro in 2026 for three reasons: older hardware that fails Windows 11’s TPM/CPU checks, legacy software or industrial devices certified only on 10, and rebuild/recovery work on existing licensed machines.

How do you download the Windows 10 ISO and write it to USB?

Official source only: microsoft.com/software-download/windows10 → Media Creation Tool (USB) or direct ISO + Rufus (GPT/UEFI for modern boards). The image is ~5-6 GB on an 8 GB+ stick. Third-party mirrors are where tampered images come from – full details in our official ISO download guide.

Install and activate

Boot from USB → Custom install → skip the key → pick Windows 10 Pro if asked. After setup: Settings > Update & Security > Activation > Change product key. A previously-activated PC re-activates its digital license automatically; a fresh build needs the new key pasted in.

Is Windows 10 Pro still worth installing in 2026?

Updates: without ESU enrollment, a Windows 10 device receives no security patches – consumer ESU enrollment is free/simple and covered in our ESU enrollment guide. Browsers still work, but an unpatched OS is the risk, not the apps. Upgrade path: if the hardware passes the Windows 11 eligibility check, moving to 11 is the longer-horizon play – keys and options in the 2026 buying guide.

Related install guides: Windows 11 Home install | Windows 11 IoT LTSC 2024 install.

Frequently asked questions

Will a Windows 10 Pro key still activate?

Yes – genuine Windows 10 keys continue to activate online in 2026. Activation and security updates are separate systems.

Can I use a Windows 11 Pro key on Windows 10?

No – keys are edition-generation matched. A Windows 11 Pro key activates Windows 11; for this install you need a Windows 10 Pro key.

Is Windows 10 Pro safe to use now?

Only with ESU security updates enrolled, and ideally on a device that is not your main internet-facing machine. For daily drivers, Windows 11 on eligible hardware is the better choice.

Need a genuine key for this install? Buy a Windows 10 Pro OEM key – instant email delivery, 14-day refund guarantee.