我的产品密钥不起作用. 如果 Office 产品密钥不起作用，或已停止工作，应与卖家联系，申请退款。 如果产品密钥是独立于软件购买的，则很可能是被盗的产品密钥，或者是以欺骗方式获得随后阻止使用的产品密钥。

Use criteria in an Access query to find specific information from your desktop database.

Microsoft made a commitment to provide 10 years of product support for Windows 7 when it was released on October 22, 2009. This 10-year period has now ended, and Microsoft has discontinued Windows 7 support so that we can focus our investment on supporting newer technologies and great new experiences.

使用电脑健康状况检查应用可以获取有关 Windows 设备运行状况的最新信息，从而帮助你采取措施提高设备性能和排查性能问题。

Get the most out of your subscription with expert advice and support from small business advisors. Business Assist for Microsoft 365 is designed for small businesses to give you and your employees around-the-clock access to small business advisors as you grow your business, from onboarding to everyday use.

Contacts can be exchanged between Outlook and Google Gmail to save time and avoid manually re-entering your contacts.

Learn how to use Narrator, a screen-reading app built into Windows, with this complete guide and how-to articles.

With External Access for Teams, you can add or invite anyone outside of your Teams org who uses Teams, Teams for personal use, Skype (for consumers), and Skype for Business to a one-to-one chat.

La aplicación Comprobación de estado del PC te ofrece información actualizada sobre el estado de tu dispositivo Windows. Esto te permitirá tomar medidas que mejoren el rendimiento de tu dispositivo y solucionen problemas que lo puedan reducir.

Get help with Outlook for Windows, the Outlook app, Outlook.com, and more. Find training videos, how-to articles, and Outlook support content