Default Gateway Not Found

I am having a strange issue with a PC at the place that I work. The problem started with the user not being able to get onto the Internet. When I look at the ipconfig /all, I notice that there is a valid IP address, mask, etc. The only thing that is missing is the Default Gateway (it just shows up blank.) At first I thought it was the Linksys hub that is was plugged into but I took that out of the equation. I also switched ports on the HP ProCurve 2650 switch that the drop goes into and still the same thing. I can ping the gateway and if I manually enter the addressing information into the NIC, the PC works fine. The same is also happening to the other PC attached to the Linksys hub. Any help would be greatly appreciated. Thanks.