Learn about the recovery options in Windows. Find out how to reset your PC, go back to a previous version of Windows, or use media to reinstall Windows.

Microsoft Support offers assistance for Microsoft products, including how-to articles, videos, and training for various software and devices.

Learn how to remap buttons, adjust stick sensitivity, and update firmware for your Xbox Elite Wireless Controller Series 2.

Alternatively, you can install any website by going to the top corner of the browser and select Settings and more … > Apps > Install this site as an app. Once the application is installed, it will appear under edge://apps.

查找 Windows 7 或 Windows 8.1 的产品密钥. 卸载或重新安装 Windows 7 或 Windows 8.1 时，通常需要产品密钥。 通常，如果购买的是实物 Windows 拷贝，产品密钥应该在标签上或者在 Windows 随附包装盒中的卡上。

Learn how to get Microsoft Store updates for your apps and games. Download the latest versions of Microsoft Store apps and games.

Learn about the quotas and differences between Microsoft storage and email storage.

Learn how to filter the contacts in the People app on your Windows 10 PC so you can see all of your Skype contacts.

The Program Install and Uninstall troubleshooter helps you automatically repair issues when you're blocked from installing or removing programs.

可以使用 简单的公式对) 一组单元格 (区域中的数字求和，但在处理多个数字时 ，sum 函数 更易于使用。 例如，=sum (a2：a6) 出现键入错误的可能性小于 =a2+a3+a4+a5+a6。 下面是使用两个单元格区域的公式： =sum (a2：a4，c2：c3) 对区域 a2：a4 和 c2：c3 中的数字求和。 可按 enter 获取总计 39787。