When you say you can ping the website are you talking about external webpages?

If so, what I am to understand is only the billing PC's (which have DHCP reserved IP Addresses) cant access the Internet but can view the Intranet with no problems?

Have there been any new GPO's released? Is there any screwy stipulations setup on the DHCP server? Reservations that are odd or anything? Any new updates, patches in the environment that would lead to these issues?