Is it just Wikipedia that won't load? Try typing 145.97.39.155 into the address bar - that's the IP address for en.wikipedia.org. After a quick test, I see it won't actually take you to the main page, it will take you to an error page (with the foundation logo) because it doesn't know which project you want - let us know if you can see that error page. If you can, it sounds like some kind of DNS issue. If you can't load that error page, and it's only wikipedia that's a problem, then something very odd seems to be going on...