Power supply

Okay - I feel like a total dweeb...

I've got my brand new Arduino here - and I've been coding away for days. I've come to the point where I would like to unteather my board, and hook a 9v battery up to it.

I take a stab at it, and plug the + into the 9v port, and the black into the GND - after switching my jumper of course. Success - power! Nothing happens though!

It powers up - my LED flashes confirming Bootloader, but my program never loads. My TX/RX lights are on solid, and don't turn off. I try resetting it - they just flash brighter. When I switch back over to USB power, my program boots right up and goes to town.

Am I missing something here? Is there like a "boot" button or switch or something?

This has ruined my productive night :'(