Let me start by saying I'm not a "car guy". I know enough to take a car to the shop when it's not working correctly, that's about it.

I went to go to work this morning and when I turned my key in the ignition, everything just went dead. Lights went out, etc. I can't even lock the doors now, that is how dead everything is. Could this be a fuse of some sort? The battery is less than a year old, and it seemed to be fine when I first got in the car (doors unlocked with remote, lights came on, etc). If it is a fuse, where are they located? I assume there's a fuse box somewhere under the dash?

It's a 2005 Mini Cooper.

 

Found the fuse box (driver's side), no idea how to tell if a fuse is bad. I guess I will be calling a wrecker service.

 

There really isn't one fuse that a single point of failure for 'everything'

I'd see if the car can be jump started ... this will tell you many things.

Most important, of it does jump then your system is working correctly other than the battery.

If it does jump then you either have a bad battery or a bad connection. It is not unusual for a battery connection to not be tightened correctly when the battery is changed and eventually things just stop working. Or you may have a bad battery.

 

There is actually a main-fuse in a little junction box just off the battery on my R53 - not sure if they did it the same on the justa with the front-mount battery and all, but you might want to trace the positive lead a little ways and see what you find. FWIW, mine just did essentially the same thing, and the dealer found it to be a result of no power at the fuse box (duh). The key there is that something upstream from the fusebox failed, which in my case was an aftermarket cut-off switch... But a blown main-fuse could do the same thing.