Okay, here's the weirdest thing. I just got a new wireless card for my laptop, and so I decided to try it out (I got a new one for a completely different reason from the one I posted here).
Well... it works like a charm! I can access *all* the websites I couldn't otherwise access. Yet it's a wireless card, so the connection goes through the router as well!
So it's obviously not Wanadoo that's responsible for the issues (this time). But I still don't know why I can't get websites when I connect to the router through a LAN (can't be the cable unless *both* cables are faulty and don't let me access the same websites).
Kaethel