Yes your PC is protected
keep in mind you don’t need two sandbox running at the same time Comodo and Avast, the only sandbox you need is Avast not Comodo cause this is over killed.
Your Comodo Defense+ is still enable this is how it works without using Comodo Sandbox.
The Defense+ component of Comodo Internet Security (hereafter known simply as Defense+) is a host intrusion prevention system that constantly monitors the activities of all executable files on your PC. With Defense+ activated, the user is warned EVERY time an unknown application executable (.exe, .dll, .sys, .bat etc) attempts to run. The only executables that are allowed to run are the ones you give permission to.
Defense+ also protects against data theft, computer crashes and system damage by preventing most types of buffer overflow attacks. This type of attack occurs when a malicious program or script deliberately sends more data to its memory buffer than that the buffer can handle. It is at this point that a successful attack can create a back door to the system through which a hacker can gain access. The goal of most attacks is to install malware onto the compromised PC whereby the hacker can reformat the hard drive, steal sensitive user information, or even install programs that transform the machine into a Zombie PC.
Defense+ boasts a highly configurable security rules interface and prevents possible attacks from root-kits, inter-process memory injections, key-loggers and more. It blocks Viruses, Trojans and Spyware before they can ever get installed on your system and prevents unauthorized modification of critical operating system files and registry entries.
I forgot to tell sorry set your Firewall Security Level to Custom Policy and set your Defense+ Security Level to Paranoid Mode and finally look for Stealth Ports Wizard and pick Block all incoming connections that all 