Why can't I open Wikipedia, Facebook and Yahoo answers?

[spinthewheel]

I use a Mac and in the past few months suddenly I haven't been able to open the above websites. I have to switch to parallel Windows to open them and it's really frustrating. My partner is a computer whiz but he can't figure it out either. He says I managed to do something very weird with my computer. Any ideas?

[SilverTonguedDevil]

STEP 1 : Tell what you have (model of computer, screen size, processor type, processor speed, OS version). You can get this info from "About This Mac" in five seconds; it isn't hard.

STEP 2 : Come back here to Yahoo Answers, and add those details.

STEP 3 :

EDIT:
Yes, I know how to fix it, but the steps are different for different systems. Do you want help?


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