I am a beginner user. I installed the free version. After the 30-days period expired I registered my install and connected Avast to my account.
Now I am informed that all shields are active. However, the security center (I use Windows XP 32 bit with all service packs and updates) warns me that “avast is not active” and that I am unprotected. In My devices - Active protection I am informed that only the web shield is on, whereas the Mail shield (which I don’t care for) and the File System Shield are off!
I would like to understand whether Avast is protecting my computer in real-time (i.e. when I insert a flash drive) or not. I would also like to understand what is this File System shield, and why the security center keeps issuing warnings (which it had never done during the first 30 days).
All help appreciated 
I never dealt with such a complex, involved antivirus system before :-\