|Tell us more about it - are you getting an error message or is this being reported by Avast?|
Are these 7-Zip files some that you made and are they important to you? If you know nothing about them then they might be something to do with a virus.
I would be inclined to run another MalwareBytes free product too as it can sometimes unearth what your AV will miss. Install and run this:
Let it fix anything it finds. If there is anything severe reported your computer might need more attention.
Always pop back and let us know the outcome - thanks