Capture client desktop as video format

I need a program that will record everything a user does on the screen. I don't mean record keystrokes and stuff. I mean record everything on the screen as if you were just watching the monitor screen. It should also record all the sounds that occur while recording. This program should always be running in the task bar, and you should be able to start the recording with a shortcut key that a user can set. Also there should be an option where the user can save the recordings. The recording format should be in AVI or any other video format. Details of the project: A Web application which can record client desktop interaction as any Video format. Completed developed in and around .net framework. (Sample website for reference - [login to view URL]) Note: 1) No API should be be installed in client environment. 2) Interested freelancer should be ready for a demo, then afterward the project will be reward to them.