Note: licensekey here is the activation key that corresponds to your Windows edition). Here is a list of Windows 10 license keys for you. Use command “ slmgr /ipk licensekey” to install a license key. Select the start button and search for “ cmd” ,then right click on it to run it with administrator. Without any third party application you can activate your windows in one go. METHOD 1 – Activate your Windows 10 using CMD ( Command Prompt) So, here are we to help you resolve this issue permanently. Also a watermark keeps on appearing at the lower-right screen and of course it would be very annoying to have the watermark on screen and also you can’t personalize your own device or pc. When later anytime after you reinsta ll your Windows 10, it will ask you to activate the Windows. Follow the tutorial to Permanently Activate Windows 10 (any version) absolutely free, Here are the top 4 ways.