Check your home page settings. Firefox can open multiple home pages. They are separated by the "|" symbol. See: http://support.mozilla.com/en-US/kb/How+to+set+the+home+page

Could the following items you have added have anything to do with your problem: hotvideobar or gamieplay? Look at the "User Agent" at the bottom of your post.

I had the same frustrating problem and now I don't. When you want to access the internet, instead of "double clicking" on the Firefox icon, "single click" and you will open one page instead of two. Or you can right click your Firefox icon and click open. Either way it works.