I have internet Security Plus - 2 years.

Hello ?
 
Welcome to the Webroot Community,
 
Yes you will have enough protection with Webroot. Emails aren't scanned by Webroot, but as soon as you try to run a malicious attachment WSA would block the execution and protect your PC. Also if you would click on a link in an email the URL will be scanned against the cloud database.
You have to keep in mind that WSA works a bit different than other antivirus solutions; instead of scanning everything all the time and wasting hardware resources, Webroot tries to intelligently protect your PC against threats.
 
Please read the potential Webroot has.: https://community.webroot.com/t5/Webroot-SecureAnywhere-Antivirus/Scanning-PC-suspiciously-fast/m-p/... also the Webroot WIN Cloud does all the work not your PC: http://www.brightcloud.com/platform/webroot-intelligence-network.php
 

 
Here is the PC User Guide This guide will help you out alot!