1996 Windstar (ele.. problem)

My 1996 windstar was running perfect ...until the other day, I got in my van and went to start it and when I turned the key there was nothing.
I at first though it was the alternator until I checked the battery and it was fully charged.
So I put the key in the iginition and I here this clicking noise in the fuse box. If I tinker with the key the inboard lights,radio,and everything will turn on but if I try and turn the car on everything shuts off.
I figure its in the iginition switch or in the fuse panel somewhere but I did check the fuses and they are not blown.
This is almost the same as the post below me,just a different year and a few more different problems
Any help ..........please

Go a head and clean your battary termenals

I did that already, and no luck......

I found the problem today, there was a dead short in my battery, I bought a new battery and everything is fine......

I had this same problem. I replaced the battery, and everything starts fine now.

HOWEVER, now my air bag light comes on blinking, then after a small distance of driving it stays solid. Are the two related? Or is there somthing that I may have messed up when replacing the battery?

I have checked my fuses, and they are all good. 1998 Windstar.

Any help would be appreciated.

Upon further research I see that my error code is 52 Backup Power Supply - Voltage Boost Fault. however I find nothing on whether I can fix this myself or if this is a dealer issue... does anyone have further information?