comodo

Do I need to have a downloaded antivirus, isn't windows defender good enough? I did once have an antivirus program called Comodo. I have had once had windows defender, not like a program but Comodo didnt think it was a virus. I just want to know if I need an extra antivirus or not.

When i try to click on anything in Comodo Antivirus interface, nothing happens. I dont know what causes this problem and i would like to solve this, so i can use it again :(

I've used chrome for years, and comodo firewall and HIPS protection for some months, but suddenly google chrome started crashing as soon as it was loaded. I tried to reset my user profile and reinstall the program, but nothing changed, and loading it in Comodo sandbox didn't lead to any results...