The FBI notice is a weak attempt at a scam... Just ignore it. It can pop up on your smartphone, too. You may have to restart your device. There is a very real threat from the CryptoVirus which is going strong right now. It will typically come in the form of an email with a resume attached, for example. If you click on the attachment it will unleash a virus that will begin to encrypt all of your files. If you're on a network it will attack the company's main server. You will have to physically shut down the workstation where the email was originally opened on to stop the progress. Then you will need to completely wipe that hard drive and do a fresh install of Windows, applications, and drivers. Hopefully you will have nightly backups of your data so you can restore the data. The alternative is to pay the ransom to the criminal cyber gang via bitcoin to get the codes to unlock your data.