I highly recommend having a Security Suite to protect your computer. It doesn't get much better than free! Panda Internet Security is offering a free 6 months subscription. You do have to put up with at most 6 nag screens per day though. It found viruses that other anti-viruses I have tested did not.
Click on the link and save the installer to your computer.
**Please make sure no other Security Suite or Anti-Virus is installed on your computer. (Malwarebytes is an exception, it won't cause a problem)
Click on the installer you downloaded and let it install.
That's it you are done! Enjoy the real-time protection offered by Panda.
Just hope you are okay with a few popups from Panda begging you to pay.