Hello,
Welcome to Microsoft Community.
Try repairing Office 2010 and then try to open the Word file in Word 2010.
From Control Panel navigate to Programs and/or Programs and Features.
Right-click on Office 2010 and click on Change > Repair or just select the Repair option.
After completing repair make sure to restart the computer.
Check if you are able to open the Word .docx files with Word 2010.
Try the above step and let us know the result.
Thank you.