Hi, I want to call my client at the overseas by using skype or any other software which able in the internet video call.

The problem is: they don't need to see me. I want them to hear my voice, and I want to show my computer screen to them (I am running a software and presentation).

I can use webcam and put it in front of my computer screen to capture my computer screen, but it doesn't look profesional.
Do you know how to disable a webcam output and show them the monitor screen instead?