Everytime i download avg anti virus from cnet it sets up and then right before it finishes it says file incomplete every single time so i dont know if i need to try a different one or what but why does that keep happening?
^^ Exactly. Avg send info of all virus' it blocks and finds in you scans back to Avg so they can build in the improvements into their paid version. They don't test their antivirus, their free users do it for them.
McAfee All Acess is a good choice, going on 5 devices including PC's, Mac's, and Android phones. It also includes other software like SafeKey and remote tracking and wiping support.
If you not going to pay for an antivirus, don't bother getting one at all!