注意: 删除所有内容 > 更改设置 提供了两个选项。. 打开数据擦除会删除文件并清理驱动器。如果你打算捐赠、回收或出售你的电脑，请使用此选项。 这可能需要一或两个小时的时间，但也会让其他人难以恢复你删除的文件。

Important: If your device is out of support, it is no longer receiving security updates from Microsoft and may become more vulnerable to security risks and viruses.For this reason, we strongly recommend that you update to the latest version of Windows. Each version of Windows is supported for 18 months.

Press and hold (or right-click) the MP4 file you want to play, select Open with, and then choose your preferred file player from the list of applications.

Skype help & learning. Limited emergency calling Skype is not a replacement for your telephone and has limited emergency calling capabilities depending on your country.

提示: 如果要绕过“文件”>“打开”并始终使用“打开”对话框，请执行此操作：选择“文件 > 选项 > 保存”，然后选择“打开或保存文件时不显示 Backstage”框检查。然后，关闭所有打开的 Office 应用程序再重新打开。 请注意，此更改仅影响按 Ctrl+O 访问“打开文件”对话框时看到的内容。

Digital goods like apps, games, add-on content, subscriptions, movies, TV shows, and books aren't returnable unless the offer for applicable law states that you're eligible for a refund.

When you start a focus session, a focus timer will appear on screen. To use additional focus tools in the Clock app, expand the focus timer to get the full view of the Clock app.

Missed activity emails. In the Missed activity emails section, you’re able to set the frequency of summary emails detailing your missed activity, or turn this feature off.. Chats and channels notifications. Notifications for chats and channels can be managed at a granular level, allowing you to customize your notifications to your personal work style.

Contact Microsoft Support. What's new. Surface Pro; Surface Laptop; Surface Laptop Studio 2

Microsoft Edge 是 Microsoft 推荐的浏览器. Windows 8.1不再支持 Internet Explorer 11。 相反，我们建议切换到 Microsoft Edge。 Microsoft Edge 是为了给你带来最好的上网体验而建立的，让你在浏览网页时有更多自主性，并获得更多隐私保护。