Can't Connect Via Ethernet (Sometimes)

My new ethernet shield doesn't seem to want to connect to the ethernet. I have tried running several of the standard ethernet sketches provided with the IDE but nothing happens except a connection failure. The weird thing is that last night the stupid thing actually worked, but now it doesn't.

At this point I have no idea what I'm doing wrong, any thoughts or advise would be greatly appreciated.

-Andrew

maybe it might be usefull telling what board you are using and what hardware you are using for your project, etc..

I'm using an Arduino Uno R3 w/ a Wiznet 5100 Ethernet Shield. Connected via airport extreme router.

Are you using DHCP or assigning an IP address?

Sounds about par for the course with the Wiznet shield. I gave up on mine when they failed to work reliably in the long term. Depriving it of power for a short while usually got mine working again until it decided to croak again.