How do I repair Excel on Windows?

To repair Excel within a Microsoft Office installation on Windows, follow these general steps, tailored from the provided resources:

1. Open Control Panel by searching for it in the Windows Search bar and selecting 'Control Panel'.

2. Navigate to Programs > Programs and Features.

3. Find your Microsoft Office suite in the listed programs and either double-click it or right-click and select Change.

Next, choose between the Quick Repair or Online Repair method:

For Quick Repair:

1. Check the appropriate radio button (this option is quicker, but less comprehensive).
2. Click the 'Repair' button. You may be asked for administrative permissions; confirm them.

For Online Repair:

1. Choose the respective option based on whether you have a Click-to-Run (C2R) or a Volume Licensed edition:
   • C2R Edition: In the 'How would you like to repair your Office programs?' dialog, select 'Online Repair', then press 'Repair'. Note that Administrative Credentials may be required during this process.
   • Volume Licensed Editions: From the change view, select the 'Repair' option and continue with the prompts until repairs finish.

If these initial attempts fail to solve the issues, consider the last resort of doing a clean reinstallation:

• Back up essential data.
• Optionally, download a Microsoft Office ISO from sources like heidoc.net's Microsoft Windows and Office ISO Downloads Tools section.
• Fully remove the existing Microsoft Office suite using the control panel uninstall feature OR counterpart tools like the Microsoft Office uninstall specialized tool found at microsoft.com support pages.
• Reinstall your chosen version of Microsoft Office using the downloaded ISO file.

Remember that completing a thorough antivirus scan prior to beginning these processes, along with having battery backups in case restarts cause additional complications, could aid in addressing strange behaviors in Excel and other Office applications in Windows effectively.