You should never run a PC w/o an antivirus and an inactive firewall. I have both Windows and a Mac and both have an antivirus and the firewall enabled. When Chromebook needs them,in they'll go. Get an anti-virus,an anti-malware and enable your firewall. Good free anti-virus are Bitdefender,Panda Security,360 Security,Avast,Avira,AVG,Sophos Home,and Kaspersky. For an anti-malware SUPERANti-spyware or Malwarebytes. Firewall,either the built in Windows firewall,ZoneAlarm,or Comodo free firewall.