roblanderson - What is the make and model of your router? Can you temporarily connect the Xbox and PC together and see if the symptoms change?
roblanderson - what other tasks happened yesterday or the day before the Xbox could not longer connect? Did you install any 3rd party applications?
Can you check your PC's history over the last few days using the reliability and Performance Monitor?
I had our wireless company out tonight for a different reason and had them reset all of our network setup. I was able to connect the extender and the PC again, so it was an issue with the network. I'm not sure what may have caused the problem, but resetting everything allowed us to start over.
Thanks for the help.
Rob