Scam On Computer

I have had my problems w/computers when looking @ areas that I shouldnt be looking @, but last week my screen was taken over by the " FBI" not real they ask you to go to some place and get a green check and it is automactilly sent to these people & your computer is sent back to clear it up TOTAL BULLSHIT if your screen keeps taking you to this website where it says the FBI have taken over your computer. CLICK ON CRTL/SHIFT & ESC UNTIL YOU GET TO A SCREEN WHERE YOU CAN RUN MALWAYRE ,NORTON AVG WHATEVER DO IT SEVERAL TIMES AND THEN U W/BE ALL SET.