You could try something like this on your Mac(this is the Windows version) - Right click on Desktop>View>Make sure "Show desktop icons" is checked.

I'm having trouble seeing this as a Firefox problem. I presume you have re-started your computer.

Firefox 4 uses a new build-in home page named about:home with a Google search bar on it.
That about:home page only shows some snippets and has a button to restore the previous session if applicable.

If you want a home page with extras then set another page as the home page like www.google.com or www.google.com/firefox as used in Firefox 3 versions.

• https://support.mozilla.com/kb/How+to+set+the+home+page

Hi krzy4kittys, I took you at your word that things had disappeared from your Desktop but if in fact they have disappeared from your Home Page, then you should follow Cor-el's advice, which is usually the best advice anyway.