Microsoft Security Essentials .
Microsoft Security Essentials (MSE) is rated as one of the best anti-virus programmes, whats more, it is free.
Spyware is becoming increasingly popular as a method of advertising. It causes pop-ups to appear, will slow your PC down to a crawl (if you are lucky to get that fast!!), may stop you opening files or simply stop your PC from working. To get around this, we recommend Malware Bytes
be installed on your PC and that it get updated and a full system scan is run at least weekly. Malware Bytes is FREE.
Malware Bytes does not run all the time, unlike some other programs so will not slow your PC down at vital times.