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Have you tried removing Google Chrome and see if Facebook will load correctly?

have you ran a virus scan on your computer to see if you have a virus or malware

I would recommend using a different virus scanner than the one you are currently using. I would recommend Malwarebyte's Antimalware which can be ran in safe Mode which is what you need to run it in to make sure any viruses haven't corrupted AVG to give false negatives

http://download.cnet.com/Malwarebytes-Anti-Malware/3000-8022_4-10804572.html

Click on the link and click the green Download Now button. Save it to your desktop and then start your computer in safe mode with networking.

Make sure to decline the Free Trial Offer or you will have to pay for the virus removals. It should still scan fine and will remove the viruses anyway

As long as you decline the free trial offer it will be free