Here’s another winlocker based around having the victim complete surveys to unlock their computer.
This one has the user download a file with a password rather than have them just complete the survey in the locker. It requires .net 4.0 to run.
The locker doesn’t block the whole screen, but inserts itself across the middle of it and stays on top of any other windows.
Here’s the locker running in a sandbox: http://malwr.com/analysis/c32223e7aa78f4c09d883c51141e2725/