If you have a Windows 8.1 Pro 32/64-bit license key from DreamSpark and you want to upgrade a secondary computer to Windows 10 (already used through the Insider Program), you have a few options: 1. Using the Insider Account for Upgrading: - You can use the ISO you downloaded to perform a clean install or upgrade on the secondary computer. - When prompted for a license key during the Windows 10 installation, you can skip it, and Windows 10 should activate automatically based on the digital entitlement from your Insider account. 2. Clean Installation with a Windows 8.1 Key: - If you prefer a clean installation rather than an upgrade, you can install Windows 8.1 Pro on the secondary computer using a different key. - Activate...