What is the actual reason behind Google Toolbar not being available for Firefor 4.0+ and in Google Crome?

Never heard of this, go to Tools, Options, General, you will see the home page, will have whatever the home page is, strike it back to http// and type in Google.com, if you have strange toolbars at the top of Firefox , right click up there and untick, (un check) any or all. Job's done.