FBI Moneypak Locks computer. Please help

Last night I was surfing the web when norton starts to freak out and say its blocking some malware from attacking then my system locks up and I get a screen to that says that the FBI is freezing my computer and that I need to pay $200. I didnt have time to fiddle with it last night but now i have a bit more time and so i started my computer up in safe mode, and ran a norton virus scan to see if it would find anything. It came up and deleted 20 cookies but nothing else. Thinking the problem solved i restart my computer in normal mode and the same thing happens as before (computer locks with FBI message). So now after restarting again in safe mode where the virus/malware dosn't seem to be working I come here to ask for help.