Using ClamXav, please help

Hello, I am using a 2013 MacBook Air and have recently noticed some issues that, having done some research, indicate that I could have a "virus". These include:

- Many pop-up ads on Chrome where previously I had none

- Search engine being automatically changed from google to bing on Chrome

- MacKeeper running on my computer without me (willingly or knowingly) having installed it

- Chrome shutting down but not in the usual way where an error message is shown on reopening "Chrome shut down unexpectedly".

I went ahead and installed ClamXav and ran some scans which produced items with high and medium level concern which I quickly deleted. I learnt that this is inadvisable after the fact but not being a particularly savvy computer user, I freaked out and thought the best course of action was to remove them.

My issue, that I hope someone could help me with, is that I have 3 items remaining on ClamXav that cannot be quarantined or deleted and I am not sure what it means. Please see below.

Any advice regarding what sort of situation I have found myself in and what I should do next would be greatly appreciated.

Thank you.