Learn how to tell if your Office software is genuine. To help determine if your Microsoft software is genuine, go to our How to Tell site for more information. Here you'll learn about authentic packaging, including what to look for with product key labels, and Certificate of Authenticity (COA), how to report counterfeit software, and find out what your shopping and licensing options are.

Learn how to run Windows Update Troubleshooter to resolve errors downloading or installing Windows updates.

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Find operating system info in Windows 8.1 or Windows RT 8.1. To find out which version of Windows your device is running, press the Windows logo key key + R, type winver in the Open box, and then select OK.. If your device is running Windows 8.1 or Windows RT 8.1, here’s how to learn more:

但如果需要测试多个条件，例如我们假设所有条件都需要为 True 或 False (AND)，或只有一个条件需要为 True 或 False (OR)，或者如果想要检查某个条件是否不 (NOT) 符合你的条件，这时该怎么做呢？这三个函数均可以单独使用，但它们更常见于与 IF 函数成对使用。

Xbox Support offers help for Xbox, Game Pass, and billing questions. Get advice and customer service in the Xbox Support community.

如果麦克风功能出现问题，则以下信息可以帮助你排除故障和解决问题。 确保应用有权访问麦克风. 如果在更新 Windows 10 后未检测到麦克风，则表示你可能需要先授予应用相关权限才能使用它。

Windows Security provides built-in security options to help protect your device from malicious software attacks. To access the features described below, tap the Windows Start button, type windows security, select it from the results, and then select Device security.

Before you start. Check these things before you start troubleshooting Bluetooth on your device: Check your product information. If you’re setting up a new device and Bluetooth is missing, check the product specifications to make sure it has Bluetooth capabilities.

On the settings page for that app, change the setting for Let this app run in the background.Here’s a summary of each option: Always.The app is always allowed to run in the background—receive info, send notifications, and stay up to date—even when you’re not actively using it.