Screwed up the free antivirus installation, I think, how can I tell?

I basically am really paranoid with security, so while I started the setup( I didn't begin the installation, but the setup downloaded some files) I pressed on the setup again, just to check the publisher. I said to myself that it might overlap something, so I cancelled the setup and pressed it again. The installation went fine, but when you first start the setup, it downloads something first, maybe files for the installation. How can I tell the antivirus is installed incorectly or not?