For most users anti-virus is a must have. There's loads of great free options available, Avast, AVG and so on, take your pick. Just download a redistributable version of one of them, copy it to each pc and install. Update each one then shut down the router and scan every pc.
You can download the 32bit version of AVG here just click on the link on the right hand side of the page where it says
You might need the 64 bit version for your pc's so check first.
You can download the 32bit version of AVG here just click on the link on the right hand side of the page where it says
Download
Latest Version
151.20MB
You might need the 64 bit version for your pc's so check first.