Here's how to record a video of a particular area of your screen with CamStudio:
- First open CamStudio
- Click on the Region menu > Fixed Region
- In the Fixed Region dialog, hit the Select button
- Your mouse cursor will change form.
- Click/hold and drag the mouse cursor over the area of your choice (a dotted rectangular box shall appear around the area)
- Click on OK to close the Fixed Region dialog and hit the Record button to start your recording
- You shall noticed the green markers blinking around the selected area.