Its called ransomware and you'll need to take your computer to a repair service and have it removed professionally. It will pop up if you try to download MalWare Bytes and won't let you download any virus removers from the net. It moves around and renames itself in the registry constantly and worse case scenerios you'll have to wipe your hard drive. Same thing happen to me. Like to get my hands on the person that wrote this and wring their nerdy little necks.