Reveton Virus

The Reveton Virus operates on the Citadel software platform. The virus directs you to a drive-by website, and once you leave, you will get a message that freezes you computer that says it is from the FBI and says that you have violated US law about copyright infringement. No more accessing the computer. At the top of the screen is a message saying that to release the message, you have to pay a fine. THIS IS A FRAUD. This is where life or "death" come in. Now, I suggest you take the computer for a visit to a computer professional.

"First: Don't panic. (Fear is the mind killer.)
If asked to enter a form of payment, credit card, or personal information into any web window you did not specifically request, do not do so.
If you have already paid (or somehow manage to bypass the lock), you’re not out the woods yet. There may still be malware running on your computer that can impact your privacy or security. Contact a Geek Squad Agent through our Online Support website, by phone at 1-800 GEEK SQUAD, or at a Geek Squad Precinct in a Best Buy store near you."

From GeekSquad

This is the scene:

"So you’re sitting there, innocently using your computer, when a window flashes on the screen, bearing the logo of the FBI. You’ve been locked out of your computer for breaking some not-too-specifically-identified copyright law. The solution on the screen? Pay a fine to the “FBI” to “unlock” your computer and use it again."

FROM GEEKSQUAD