I doubt the router is blocking the sites. But you can access your router configuration menu at the IP address of your router.
The IP address is probably 192.168.0.1 though it could be 192.168.1.1
This is, if it has not been altered. But be careful when you go trough the settings, change something vital and you will not have any internet left to use.
But like I said, it probably is a software suit on your computer blocking the pages. I would check if you have an internet protection suit that blocks the sites.