Excel File Format Troubleshooting

I encountered an error when trying to open an .xlsx file. It appears that the file format or file extension is not valid. I have tried opening the file on another computer and with another program, and it worked fine. I need an expert to diagnose and resolve the issue on my computer.

Ideal Skills:
- Proficiency in Microsoft Excel
- Experience with file format troubleshooting
- Good problem-solving skills
- Ability to explain technical issues in simple terms.