I got a pop up saying my computer was at risk.

I am new to the community so please be patient with me. I have a MACBOOK PRO and use google chrome as my server. I was online when I got two pop ups that stated that my computer was at risk. I know this is a scam and tried to close it but it froze my window. I had to push the ok button that they provided just to get the pop up to go away. I then forced quit google chrome. My concern is the possibility of any spyware, viruses, adaware, trojans or anything being put on my computer just with this incident. PLEASE help...what do I do? thank you so much. Here are the pics o the pop ups.