A couple days agoo the toolbar that Google Search and others (that I don't use) disappeared. This morning, the ability to listen to music on Youtube ceased. I know I have sound because I can hear videos posted on Facebook (that aren't Youtube) I tried doing a System Restore but after several minutes of attempt a message came on stating that it couldn't be done, because of my AVG antivirus. They want me to temporarily disable it. Why is my computer causing things to stop working or disappear? I am using Windows 7 and Google Chrome.