How to remove a blog virus???

In the last couple of weeks, I have had readers complaining that my external links (facebook, online sweeps, etc.) have been giving them Norton popups and in some cases, nasty viruses. I am not sure when it started exactly and I’m not very sure where to even begin trying to remove this thing. Do any of you have any advice on where to start. Here is my blog https://www.sweetdeals4moms.net/ Oh and one reader said that Norton told her the virus is coming from sweetdeals4mom.net/wp-content/themes/pixelhappy/images/icon-dot.gif which brings up another image that it not mine….. Thanks in advance for your help.