to be honest i had the same problem, a few months back, i previewed a u15 idol photo and a pop up appreared and said im looking at child porn and locked my computer while saying a investigation was under way. After a long few weeks of frustration and complete panic i relised that the whole thing was a virus and its a huge problem lately. It comes up with a box accusing you of child porn and after wards askes you that you pay on line mostly through akash or something different as it changes a lot. Beleive me unless you have other where i would not worry, trust me its a load of rubbish, dont loose sleep man i did and its not worth it. Not only that the police dont even do that on the internet to catch child porn anyway, they addmitted it on the news once saying the whole thing is a scam and if they did suspect child porn the police wont talk to you over the internet they will come to your house,
I hope this helps
Buddy