Safari/firefox can't connect to facebook.com/google.com

In both Safari and Firefox, I cannot get certain websites to open.

Apple.com, cnn.com etc. all work.

http://www.facebook.com, http://www.google.com (and subdomains like http://www.news.google.com) do not work on either FB or google (and very select others). Most sites DO work.

Oddly, httpS://.... for the same sites DOES work. (E.G. https://www.google.com works)

In safari I get this error message:

Safari can’t open the page “http://www.google.com/” because the server unexpectedly dropped the connection. This sometimes occurs when the server is busy. Wait for a few minutes, and then try again.

I have tried several different DNS providers (8.8.8.8, 8.8.4.4, 208.67.222.222, 208.67.220.220) with the same results.

I looked at my host file and it is unaltered.

I'm running updates now, but don't think that is the issue 9I'll know soon).

All the other mac and PC computers on this network are working just fine and get to the sites with no errors.

Any thoughts??