Things to try:
1. Reset Firefox (just google RESET FIREFOX for instructions)
2. Delete (or rename) our Firefox profile. It will make a totally new one when you start it again.
If it's a Firefox issue, this will certainly resolve it.
Lately I see two lines of Chinese characters on top f the screen of my Dell Windows 8 computer when I use Firefox and do searches. Does this mean someone has hacked my computer and is spying on me? I am concerned because I often do financial deals like paying bills and ordering things on this computer. Who can explain what is going on?