Services window will appear, Under Name, select Messenger service by single clicking and then double click on Messenger.
Messenger Properties window as shown above will appear. Under Service status, click on Stop to close the Messenger service. The Messenger service should now be shown as "Stopped" opposite the "Service status".
In the same Messenger Properties window, click on down arrow, opposite to the "StartUp type" and click on "Disabled". This will ensure that when the System Software starts again, the messenger service doesn't start again. Click on OK to close the Messenger Properties window.
Now, close the Services window by clicking on X.
Your PC should now immediately stop getting the spam pop up advertisements that were earlier appearing again and again.