Not Found The requested URL /index.php was not found on this server.

[DaleZA]

Any help will be appreciated.

I upgraded my site from 1.7 to 1.9 about 1 month ago. All went well.

I am now getting the following error: 

Not Found

The requested URL /index.php was not found on this server.

I have commented out and changed I have commented out Rewrite engine in .htaccess

this is a live site, so I am desperate for any assistance. 

[JLHC]

May I know the reason you commented out the Rewrite engine in the .htaccess file? 

Did you perform any other modifications to the .htaccess file?

Can you try replacing the .htaccess file with the default file supplied by Magento and see if it works? 

Finally, just to confirm if the index.php file exist or was it deleted / removed somehow? 

[Pronto]

Also check if your web server has enough permissions to read index.php