Can't open excel and powerpoint files downloaded from Internet
Welcome to the Microsoft Community.
A few more details would help us to provide a better suggestion:
1. Are these files downloaded from one particular website?
2. Are you opening the files directly from the website, or are you saving it on the computer and then opening it?
3. Are you able to open the Excel/PowerPoint files that are created on the computer?
4. What is the exact/complete error message that you get when you open the downloaded files?
After saving to the computer, you may check if the files are blocked, and if yes, unblock it.
a. Right click on the file, select ‘Properties’, and click on 'Unblock' in the ‘General’ tab.
b. Also uncheck the box for ‘Read Only’ in the ‘Attributes’ section in the ‘General’ tab (if it’s checked).
If that doesn’t help, you may repair Office 2010 from the Control Panel and check if that helps in opening the downloaded files. Refer this link on how to repair Office 2010:
Hope this helps. Let us know if you need any further information.