Nginx?

Hello, I have noticed a couple of "welcome to nginx" threads here and recall getting that message myself a couple of times last week when I tried to use yahoo search.  I just closed the window and used another search engine when that happened.  Computer has been working fine and scans by NIS and Malwarebytes have turned up negative for anything other then cookies.  I am a little nervous now though and was wondering if there is another scan that I could use to make sure my computer isn't infected by anything?

 

Thanks