Disable ads in Chat window of Skype

Right click on your network icon in the system tray.

Open Network and Sharing Center

then Open Internet Options, after that select Security Tab

click on Restricted Sites and then click the Sites button

The 'Restricted sites' dialog will appear on the screen.
Then you need to type the following text https://apps.skype.com/ and then press the Add button

Close Internet Options and restart Skype.

That's it.

Block Adverts in Skype's Contact List

Open Skype, open the Options dialogue. Under the notification sub-section, click on Alerts & messages.

Below "Show Messages About" Un-check both check boxes. 

No more creepy adverts.