I clicked on what seemed to be a picture of a seating chart for a concert, and it re-directed me to

when I clicked the picture of the seating diagram for a local theater, it immediately redirected me to a "national security agency" type website with a weird web address and it literally locked my browser/my computer from doing anything else.  It also said that everything was 'being recorded' by the government.  Hello???What gives???  Is this a virus bug?  I was just trying to see a seating diagram and buy a couple concert tickets.  Does anyone know of this happening and is it a virus, a bug?  The only way I got rid of it is turning the power down button to completely shut it down/off.   I did a scan from Webroot but found no malware, I'm still leary of doing anything now...  How do I get assurance I'm not being hacked?