1 step. in skype setings
2 step. block sites in IE:
https://apps.skype.com https://rad.msn.com https://api.skype.com https://static.skypeassets.com https://adriver.ru3. block url in C:\Windows\System32\drivers\etc
127.0.0.1 rad.msn.com 127.0.0.1 apps.skype.com 127.0.0.1 api.skype.com 127.0.0.1 static.skypeassets.com 127.0.0.1 adriver.ru 127.0.0.1 devads.skypeassets.net 127.0.0.1 devapps.skype.net 127.0.0.1 qawww.skypeassets.net 127.0.0.1 qaapi.skype.net 127.0.0.1 preads.skypeassets.net 127.0.0.1 preapps.skype.net 127.0.0.1 serving.plexop.net 127.0.0.1 preg.bforex.com 127.0.0.1 ads1.msads.net 127.0.0.1 flex.msn.com