Tip: If you're a Microsoft 365 Family or Personal subscriber you get Microsoft Defender, our advanced security software for Windows, Mac, iOS, and Android, as part of your subscription.Learn more at Getting started with Microsoft Defender.

When prompted, enter the product key. You can find the product key on the sticker on the CD case or other packaging. If you need help, see Find your Product Key for Office 2007.

An upgrade differs from an update in that it moves your PC from a previous version of Windows—such as Windows 10—to Windows 11. This FAQ is intended to answer questions about upgrading to Windows 11.

Test your camera with the Camera app. Select Start , then choose Camera from your apps. If you're asked to allow access to the Camera, select Yes.If the camera works in the Camera app, the problem might be with the app you're trying to use.

If your screen only has a Mini DisplayPort, you can set up the following connections—connect a USB-C to HDMI adapter to an HDMI cable then to an HDMI to Mini DisplayPort and then to your external screen. Keep in mind that the more adapters used, the more degraded the signal may get.

Notes: If you don't see Go to Microsoft Store on the Activation page, contact your organization's support person.. If you made a substantial hardware changes to your device (such as replacing the motherboard) and you have a valid product key, try to activate Windows by phone.

Repair programs in Control Panel. Select the Advanced options link under the name of the app (some apps don't have this option). On the page that opens, select Repair if it's available.If it isn't available or doesn't fix the problem, select Reset.

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。

Symptoms. When the operating system is in high-DPI mode, applications that use the Microsoft Foundation Classes (MFC) library of Microsoft Visual C++ 2013 may behave incorrectly.

To increase security and performance, Windows 11 in S mode only runs apps from the Microsoft Store. If you want to install an app that isn't available in the Microsoft Store, or if you have Windows 10 Pro, Enterprise, or Education and want to upgrade to Windows 11, you'll need to permanently switch out of S mode.