Spyware/malware infected my Installation

Not every time, but *most times* when you hit this link for my WordPress blog:

http://www.brelsfordpersonnel.com/blog

You get one of those fake “Windows Defender says your site is unsafe”

Blah blah blah, it’s fake.

I’ve been running WP “4.8.2”, there isn’t a TON of traffic on our Blog, and I’ve had “Akismet” running on it. Now this is happening. Any ideas how I can fix this?

I’ve tried installing this plugin:

https://wordpress.org/plugins/antivirus/

But I’m not sure it’s actually helping anything with my installation right now.

Any ideas?