This seems to happen alot for people. Usually it tends to be that Firefox is outdated or its the computer itself. (Usually on Windows 7's like your own)

First delete your cache cookies etc. and update Firefox to 35.1 to make sure it wasn't a previous bug.

If that doesn't work try using Internet Explorer just once to see if it has the same issue. If so, i am 98% sure its your computer.

If it works on Internet Explorer try to remove some of the many plugins you have installed on your Firefox. I dont recognize many of them so dont worry about all of them being default necessary plugins except

• Next Generation Java Plug-in 11.31.2 for Mozilla browsers
• Shockwave Flash 16.0 r0

I suggest you research the rest or ask here if you are unsure.

Security Issue: Update your Flash Player v16.0.0.296
https://www.adobe.com/products/flashplayer/distribution3.html

Also please update Firefox.

Press the Alt or F10 key to bring up the tool bar. Then Help > About Firefox will tell you what version have and check for updates.