Note: If it’s been fewer than 10 days since you upgraded to Windows 10, your previous version of Windows will be listed as a system file you can delete.If you need to free up drive space, you can delete it, but keep in mind that you'll be deleting your Windows.old folder, which contains files that give you the option to go back to your previous version of Windows.

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:

In the Step 1: Select condition(s) list, select the check boxes for any options that you want, and then click Next.. If you do not select any check boxes, a confirmation dialog box appears. If you click Yes, the rule that you are creating is applied to all messages that you send.

注意: 使用安装介质重新安装Windows 11，同时选择“不保留任何内容” (干净安装) ，如果重新安装 Windows 的分区为 20GB 或更大，则将自动启用保留存储。 保留存储空间将留出磁盘空间以供更新、应用、临时文件和系统缓存使用，因此可确保关键的操作系统功能始终可以访问磁盘空间，从而改进了电脑 ...

Turn your PC off completely. To shut down, select Start and then select Power > Shut down.. Sleep. Sleep uses very little power, your PC starts up faster, and you’re instantly back to where you left off.

Learn different ways to locate your BitLocker recovery key in Windows, and learn about how BitLocker might have been activated on your system.

Find your Windows settings in a snap! Select the Start button, then select Settings .From there, browse the categories or use search to find what you're looking for.

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

If you're trying to add your Outlook.com account to Outlook or another mail app, you might need the POP, IMAP, or SMTP settings. You can find them below or by viewing them in your Outlook.com settings.. Outlook and Outlook.com may be able to detect your account's mailbox settings automatically, but for other non-Microsoft accounts, you may need to contact your email provider for their settings.

Swipe in from the right edge of the screen, and then tap Search.Or, if you are using a mouse, point to the lower-right corner of the screen, and then click Search.Type Command Prompt in the Search box, right-click Command Prompt, and then click Run as administrator.If you are prompted for an administrator password or for a confirmation, type the password, or click Allow.