avast! Free Antivirus is based on multiple protective layers that work together to provide security. it comes bundled with lots of features, possibly every security feature you can find in the market, all in one. Here are some key features of "Avast! Internet Security":

There are few useful scan options by default that allows users to quickly start a virus scan, they are Quick Scan, Full System Scan, Removable Media Scan, and Select Folder to Scan. And if this is not enough, there is also an option to create a custom scan.

avast! Free Antivirus Key technologies:
1. Antivirus and anti-spyware engine
2. avast! Intelligent Scanner
3. Silent/Gaming Mode
4. Behavior Shield
5. Real time anti-rootkit protection
6. Smart virus updates
7. avast! Community IQ
8. Behavioral Honeypots
9. Green computing
10. avast! iTrack
11. File System / Mail Shield
12. Web Shield
13. IM / P2P Shield
14. Network Shield

The license of this software is Freeware, you can free download and free use this antivirus software.