I'm completely new to PHP and I'm trying to install the zip for the Windows version of PHP 7.0.11. When I extract the zip, Norton Security Suite starts removing many dlls. I downloaded the zip from http://windows.php.net/download/ and checked the SHA1. Are any additional precautions I should take before I exclude the directory where the package will be extracted from Norton scans?
You are downloading a package from the official website of an established well known and reputable piece of software:
They do not have motivation to install a virus in your machine.
So unless someone hacked into php.net and have replaced the original package with a virus or a Trojan horse - I wouldn't be too worried.
Sometime an antivirus software might detect some files as a threat because it follows a specific pattern used by the antivirus software to detect suspicious files - it does not always mean that the file in question is a real threat.
Hope it helps a bit