My latest anti-virus does not update automatically, how will i set the automatic update or should I replace my anti-virus?

I faced a new problem. I used free Antivirus.

But some malware, virus, spyware affected my Pc.

How I can removed these threads?

Good evening.

I downloaded and used this AVIRA free Anti virus in the internet for quite some time already.

Ive noticed that it doesn't have an expiry date like those other free anti virus I previously downloaded.

It automatically updates regularly too. I want some experts to ask their opinion on this.

Is this anti virus reliable to use.?

How to remove the Anti-virus previously installed in my computer since I want to install a new one?

Is it the best way to remove virus from hard disk of computer by formatting the hard disk?

If i use two antivirus programs in one system will one of them detect another one as virus?

I have idea about virus. But I don’t have any idea about spyware and malware.

Can anyone help me in this regard?

How can I understand that I have virus in my computer if I don’t use any antivirus software?

when i bought my kaspersky anti virus an installed in my computer, I followed all the steps.the computer prompted that i should uninstall Norton on the system. i did but next i try to install it prompted the same how do i remove Norton from the pc

How an Antivirus Program Works? Are there free programs we can install for free? Will it be as effective if its purchased?