Windows Activation, introduced in Windows XP, checks in with Microsoft when you install Windows or get a new Windows PC. This is an anti-piracy feature — it’s designed to annoy you if you’re using a non-genuine copy of Windows.

Luckily, Windows Activation has been toned down after its introduction in Windows XP. Even if your PC fails activation, it will continue to function until you can fix the problem — unless you’re using Windows XP. If you are, you should upgrade anyway.

How Windows Product Activation Works

Windows will prompt you to activate with Microsoft after you install it. When you activate over the Internet, your copy of Windows checks in with Microsoft and reports its product key. If your Windows product key is non-genuine (in other words, a pirated key) or is being used on another computer, the activation process will fail.

Windows can also be activated with a phone call. Windows provides a code you type in over the phone, and you’ll have to enter the code it responds with into your computer. You can also talk to a real person, which is useful if the activation process is failing. For example, if you’re moving Windows to a new computer, you may have to talk to a real person and explain the situation before they’ll allow Windows to activate.

“Significant” hardware changes can also trigger the Windows activation process again. For example, if you swap out multiple components on your PC at the same time, you may have to go through the activation process. Microsoft hasn’t explained exactly which hardware changes will trigger this.

OEM Activation

RELATED: Beginner Geek: How to Reinstall Windows on Your Computer

The OEM Activation feature helps ensure that most people will never have to deal with Windows activation. PC manufacturers insert a digital product key into a Windows PC’s BIOS during manufacturing. When you buy a PC with Windows preinstalled, Windows automatically activates over the Internet using the OEM (original equipment manufacturer) product key. You can replace much of the hardware in the computer without triggering a reactivation.

If you install a different copy of Windows on a PC that came with an OEM Windows key, you’ll have to go through the standard Windows Product Activation process. The OEM activation process only works when you use the copy of Windows that came with your computer or restore that original copy of Windows.

When Windows Activation Fails

Different things happen on different versions of Windows when activation fails or when you exceed the grace period without performing Windows Activation. On Windows XP, the operating system will be unusable after 30 days or if activation fails. In some cases, Windows XP seems to have a 60 day grace period instead.

If activation fails or you exceed 30 days without activating on Windows 7 or Vista, you’ll see a message saying you’re using a non-genuine version of Windows at the bottom-right corner of your screen. The desktop background may also turn black. Only critical updates and security patches can be downloaded from Windows Update, and Windows will regularly remind you to fix the problem and activate your operating system. Luckily, Windows will still be usable.

There is no grace period on Windows 8. If you haven’t activated your operating system, you’ll see a message with the version of Windows at the bottom-right corner of your screen. Many personalization features will also be disabled — for example, you can’t change the wallpaper if you haven’t activated Windows 8 yet.

Thankfully, the penalties for not activating Windows have become less harsh in modern versions of Windows. You’ll still be able to use your computer if you have a problem with Windows activation. Microsoft just wants to bug you into using a legitimate version of Windows and buying a legitimate product key. This feature also prevents smaller computer manufacturers from installing pirated copies of Windows on their PCs and selling them to unsuspecting buyers.

What About Windows XP?

RELATED: Microsoft is Ending Support for Windows XP in 2014: What You Need to Know

Microsoft is ending support for Windows XP on April 8, 2014, and we know that Windows XP won’t even function after the grace period if it can’t activate. If Microsoft took down the activation servers, this would be a problem.

Luckily for all those Windows XP users who haven’t yet switched to modern operating system, Microsoft has announced they’ll continue operating the Windows XP activation servers. Those old copies of Windows XP will continue to work, install, and activate normally.  In the future, other versions of Windows should continue to activate even after Microsoft ends support for them. As long as Microsoft is running the activation servers, things should continue working smoothly.

Microsoft Office also includes an activation feature that requires you activate new copies of Microsoft Office with Microsoft to protect against piracy. This feature works similarly, but Office will only function in read-only mode if it hasn’t been successfully activated. You’ll need to activate Office to create or edit documents.

Image Credit: Karl Baron on Flickr

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Chris Hoffman is Editor-in-Chief of How-To Geek. He's written about technology for over a decade and was a PCWorld columnist for two years. Chris has written for The New York Times and Reader's Digest, been interviewed as a technology expert on TV stations like Miami's NBC 6, and had his work covered by news outlets like the BBC. Since 2011, Chris has written over 2,000 articles that have been read more than one billion times---and that's just here at How-To Geek.
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