How do I remove a virus with Avast AntiVirus?

Avast has detected a virus so I scanned but it says 0 infected files. I clicked on the chest and in the infected files, it shows one item with the virus description of Unix:Malware-gen. What do I do? Do I keep it in the chest or delete it or what? Is Avast even a good anti-virus software? Because so far, I don't like it, it's hard to understand how to use too...