|There are lots of thoughts in regards to this, so research is key.|
My thought is a good antivirus, not a big fan of mcAfee, however they have made many improvements over the years. Then I would recommend Malwarebytes as a Malware scanner. There are such things as a registry locker, this would be an option as they ussually let you know when a modification is made. However, they can get annoying as they prompt for any changes.
Personally, I set up a browsing user that has limited rights, and do not use the administrator account for browsing. This limits what can be done. Also insuring that you are current on security changes will increase your defense.