Charged battery, but doesn't even try to start.

My wife's been out of town with our primary vehicle all week so I've had the pleasure of being able to drive my duster a lot more. Unfortunately just now as I was trying to leave for work, I ran into a weird issue.

When I turn the key nothing happens. It doesn't try to turn over. Doesn't make a single sound. I know the battery is fully charged because last night when I went out to get some food the car was struggling. Whenever I was just sitting at an idol it would die and I would have to start it and keep the idle fairly fast just to keep it from dying on me in the drive-thru. I just figured it was due to the cold since I didn't really let it warm up before I left the house last night. But then when I drove it into the garage when I got home, it literally died with 6 inches left to go. And it wouldn't start again.

So just to be safe I put it on the charger and let it trickle charge all night. Came out here today and I got nothing.

So what's the best bet? The ignition cable? The ignition control unit? I don't think it's the porcelain ballast simply because the last time that died on me the engine would crank and then immediately die and right now it's not even cranking.

I've been reading the manual as I wait for a ride to come pick me up and it doesn't have a lot in the way of diagnostics for this kind of problem. Anybody have any tips and tricks?