If the steps above don't work, you may need to reinstall Windows. For more info, see Windows 10 recovery options. Describes how to use the System File Checker tool to troubleshoot missing or corrupted system files in Windows 8.1, Windows 8, Windows 7 or Windows Vista.

Download and install or reinstall Microsoft 365 or Office 2021 on a PC or Mac - Microsoft Support. Office 2021 Office 2021 for Mac Office 2019 More... Tip: Get expert advice, dedicated support, and personalized guidance from business specialists.

Download and install or reinstall Office 2019, Office 2016, or Office 2013 - Microsoft Support. Office 2019 Office 2016 Office 2016 for Mac Office 2013. If this is the first time you're installing Microsoft 365 you may have some setup steps to do first. Expand the learn more section below.

Use the Office offline installer to install Office 2016 or Office 2013 if you don't have an active Internet connection or you're having problems with slow speed or unreliable connections.

Windows Server 2008. Microsoft generally releases the MSRT on a monthly cadence as part of Windows Update or as a standalone tool. (For exceptions, see Skipped releases .) Use this tool to find and remove specific prevalent threats and reverse the changes that they made (see Covered malware families ).

Microsoft Defender Antivirus is a powerful tool that finds and removes malware from your PC. Here's how to use it in Windows 10 or 11 to scan your PC. Important: Before you use Microsoft Defender Offline, make sure to save any open files and close apps and programs. Open your Windows Security settings.

PC Health Check app brings you up to date info on your Windows device health, helping you take action to improve your device performance and troubleshoot performance problems. It is periodically updated based on customer feedback to help you make the most of your Windows PC. How to open PC Health Check.

Select Install apps. Follow the instructions in the browser to download the installer and start your installation. Tip. As your apps are installing you might see the User Account Control prompt pop up and ask Do you want to allow this app to make changes to your device? Select Yes. Close the installer window after it's finished.

Option 1 - Uninstall Microsoft 365 from the Control Panel. Option 2 - Completely uninstall Microsoft 365 with the uninstall support tool. Tip: If you're a small business owner looking for more information on how to get Microsoft 365 set up, visit Small business help & learning.

Office 2007. Important: Office 2007 is no longer supported. Learn how to upgrade to a newer version. If you still need to install this version, you'll need an Office 2007 installation disc and a product key for the version you're trying to install. Install Office 2007. Insert your Office 2007 CD into the drive.