FBI locked your computer. They want a $100 $200 payment to remove the lock. It is a scam. The FBI won't lock your computer. This is a virus / malware that you received in an email.
First you have to restart your computer in safe mode. Use f8. Mine would not go into safe mode so I forced a shut down by holding down the power button. When it restarts it will say improper shut down and offer to start in safe mode. Start in safe mode as soon as it starts loading you need to push control alt del to start task manager. If the task manager starts you have to close the virus program it should be something you don't recognize. Mine actual asked to restore a previous version and a picked a date before the virus. You have to run your security virus scan so it can remove the virus. Also go to the control panel look in uninstall programs by date and remove anything you didn't add on the day of the lock out.