Locking everything up in queen Bae of nightingale city

I was fighting in Queens Bae district and all of a sudden FOS went almost to zero then when I it finally came back, I was locked out. I mean I was locked out of everything but shoot. I couldn't even use windows button; or ctrl alt delete. I had to do a hard reboot of my laptop. I have not had any FOS slowdown at all in nightingale city at all but that time.