Question: Because of some reason my site stopped working. After that I have uploaded the backup which I had created earlier.

I am getting a "404 Not Found Error The resource requested could not be found on this server!"
getting this on every page except `index.php` and also not able to login into the admin panel.

I already cleared the cache memory and set the `is_active` option to 1 in `core_website`, `core_store` and `core_storegroup` tables in phpMyAdmin still getting an error... I've tried so many links to solve this issue but the problem didn't resolved till yet.

Answer: 
It sounds like a behavior which can happen if you do not have the ".htaccess" file by Magento or if the ".htaccess" file is messed up. 

Please try adding or replacing the current file with the default ".htaccess" file from Magento.
For the temporary solution I would suggest you the following step to perform

1. Go to **System ->Configuration**
2. On left hand side select **General -> Web** and under that you will find the
**Search Engines Optimization** tab

Use Web Server Rewrites => No

I think your server does not having rewrite\_module enable please check whether it is enabled or not. Also check that your root directory containing the .htaccess file or not. You still have any problem just contact me on my skype:imrhjadeja. I will provide you more detail