It sounds like DNS isn't set up correctly if you can ping but cant get the page.
Try pinging google and then using its IP address in the browser to get to the site.
eg
... If this works then its definitely DNS settings
Check your PC has some DNS settings by opening a command prompt and typing
Also.. check your router is getting some DNS settings (preferably automatically by DHCP)
Check other websites work (ie is google the only one that isn't working?)