2.Open molecularShell/VitaShell and navigate to ur0:shell/ and there you will see a folder named whats_new. Delete it and restart your PS Vita.
3.When your Vita restarts you have to press PS button couple of times, this is so that Vita can download new advertisements.
4.When the advertisements pop-up again navigate to ur0:shell/whats_new/np/ with molecularShell/VitaShell and inside that folder you will see whatsnew.xml file. Delete it and create a folder named "whatsnew.xml" without "".
5.Restart your PS Vita and enjoy your brand new multitasking menu without those pesky advertisements.
You should know that if you rebuild your database in recovery you will have to do the same thing all over again.