Well, have you ever wonder how people capture their desktop and record it with sound and show it as a demo ?
The answer to your question will be Windows Media Encoder 9. A tools from Microsoft to let you create/show/demo product from your desktop and capture/record.
To download this software, you need to have a genuine Microsoft Windows. Else, you won't be able to download it.

 Download Link:
Windows Media Encoder 9 - 9.5 MB