From Chrome, if I log into Gmail I get a message before gmail ever starts loading: "This webpage has a redirect loop". If I try to log into facebook it says that my password is incorrect (although I can verify that it is correct via another computer). Getting another password doesn't work because it says it's also incorrect. When I move to a different browser I get similar, but not identical, behavior. Things work as expected on other computers.
I've tried removing all browser history, but that doesn't help. I've tried reinstalling Chrome, but that doesn't help.
What haven't I tried? What is the cause of this problem?