You wrote you were donwloading a movie, sound like you're using peer-to-peer filesharing (Limewire, Kazaa, BearShare, .... ) If so, you have massive spyware.
See if you can boot into Safe Mode with Networking. If you can, install/run the following;
o Malwarebytes Anti-Malware
o SuperAntipsyware
o Spybot Search & Destroy
Repost with results.
-- Andy