If you're in a rush here's an animated GIF (below on the page there is a YouTube narrated video)
The first thing is to make sure that you’re running the latest version of Skype by going to:
Help > Check for Updates
If you're running the latest version then you should see this screen
Here's a video how to fix skype’s high cpu/processor usage
Set the default program associated with .htm files.
The next step is to restart Skype or if it's easier for you you can restart your computer.