Ok, first a background. I have a 99 XJ, 4.0L, 87K miles, 242 Transfer.

So this morning Jeep started fine, filled up the tank and then nothing. When I put the key in no power at all. Somebody try jumping me, but it would just slowly crank and nothing. Replaced the battery, it was a few years old and had some corrosion on the bottom when I took it out. Hooked everything back up and had a slightly hard start but ran well all the way home.

So, later I went out to move the Jeep. Put the keys is, all the lights came on on, but when I went to start it, everything died. Then no power at all. Cleaned all the terminals and and connections at the battery. Once I tightened it all again, I could get the ignition to the on position. But when I try to start, I lose everything. There is no click, no hesitation, just lose all power.

Any help or ideas?