I have Chinese Characters showing up on the top of my Firefox page.

The Chinese Characters have been showing up for a couple of months. I have tried using various Virus Detecting programs such as MalewareBites but they don't seem to fix the problem. These Chinese Characters show up on the initial Firefox Search Screen as well as my ANZ Bank and Ancestry.com.au webpages just to name a few. How can I get rid of them. These Chinese Characters don't appear on Google or Internet Explore. If this can't be fixed I may have to stop using Firefox and use Google or Internet Explorer. I have tried attaching an image of this problem but it appears I am unable to.