You need something with real time protection malware bytes even though it does a good job scanning, doesn't offer real time in the free version. The AV program I would recommend for real time protection for free is AVG. it doesn't do as nice of a job as malware bytes for the cleanup, but it will alert and block stuff that it believes is malicious when you download it. Also disable JavaScript and only let it run on websites that you go to a lot, and also trust. The two other things that you can do to help with your problem is something I did for a friend that was downloading to many of those files no one likes to talk about. Is making a admin account, then changing your current one to have limited access. Then the other thing was just to run a sandboxed web browser such as Firefox, and installing web of trust. If you are willing to spend like $10 malwarebytes pro should be on sale for winter again @ that price. You can keep both on there though, it won't decrease your systems performance since malware bytes pretty much is a dead weight until you scan something.