Need some serious help. Virus/malware prevention?

[Anna]

I have a coworker who perpetually has malware/viruses/trojans/adware/junk on her computer. I remove a few items a day, actually. She has Malwarebytes and McAfee. We had Norton in the past, but it let a rather nasty virus through that took HOURS to remove.

She has a brand new computer, but even after starting over with fresh new software she still managed to get it bogged down with viruses in a couple of weeks. She actually has no idea where she gets it from. She maintains all she does is read news articles, check email, and get on facebook during her break.

So my question is this: What antivirus/antimalware software can you recommend to try to prevent all of these harmful things from being downloaded? Even if it's a combination of different things, PLEASE offer any advice you can.
She's in her late 50's. I honestly think she has no idea how she's getting them. That's the problem .