65 GT wiring issues?

Hello everyone, I need some major help! I have a 65 Mustang GT that I have had since I was 15. In October of 2008 something flipped out on my car. All of the sudden after all these years of starting everytime, the car won't hold a charge. I have printed wiring diagrams, looked the car over from top to bottom and cannot seem to find the problem. I have asked everyone in the world and tried everything they have said and anything I could come up with. I am at the end of my rope. This is my daily driver once again and with a 19-month-old and spring and summer fast approaching I need to get this car back reliable so we are not sitting on the side of the road in 100 degree weather broke down!

The major things I have noticed are:
1) The battery takes six hours or less to go from a full charge to nothing.
2) The negative battery cable sparks when you put it on. (I have been pulling the cables whenever I go anywhere so the battery won't run down).
3) We moved the car the other night, and the car quit (it was cold) and then when I pumped the accelerator and turned the key again the battery died and the dome lights in the car quit working.

Please somebody help me. This is killing me not being able to figure it out.  

No. 3 is probably a loose connection on the battery, from having to disconnect and reconnect it every time you use the car.  When one draws a lot of current from the battery, a loose connection opens up.

Remove the negative cable from the battery and put an ammeter in line with it.  (+ side of the meter on the cable, - on the battery).  This will tell you how much current is being drawn.  Carefully remove the fuses one at a time and see if the current stops.  If so, this narrows your problem down to a particular circuit.  

If the voltage regulator is of the old variety, it sounds like the points have stuck closed. Remove the cover and closely inspect to see if you find any stuck or burned closed. This happen to me about 15 years ago when I put in a new old style voltage reg., ran it, shut it off and went in the house. Next morning it was stone cold dead. Finally found the points welded shut on the reg. Unstuck them, filed them clean and reset the tension spring and it's still working on the car to this day. I think they make new solid state replacements which I will try should mine go bad.  

Cushman's on the right trail here.  The best thing you said was there was a "spark when you connect/disconnect the neg cable". This means you have drain in the car's electrical system. The hard part is finding it.  If you don't find a bad Vreg, start looking for obviuos things like trunk and glove box lights on all of the time. From there, start pulling fuses until the spark stops (it would be benefitial to have an ammeter installed between the neg termoinal and the cable end so you're not back and forth all the time). You'lll need your diagrams to sort out th edrain if it isn't just a light or something easily found. Good luck  

The car has electronic ignition so that is out with the points. We disconnected the trunk light b/c I thought it might be draining the battery also. We cut power to the radio thinking it might be that also. We are supposed to have a guy come over tomorrow with an ammeter so we can pull the fuses and see if we can find it. Will let yall know what I find. Thanks for the help. If you think of anything else please don't hesitate to let me know.  

We are not talking about the ignition points. The VOLTAGE REGULATOR has points inside of it controlling the charging and current draw of the car's charging system. When a preset voltage level is reached, a coil in the regulator overcomes a spring and breaks the connection of the charging curcuit, these "points/contacts" can arc and weld themselves together sometimes causing a direct drain on the battery. Again, this is a voltage regulator, not a distributor. I'm running a billet MSD electronic distributor, but I still have a voltage reg.  

Stanggirl, read Cushman's post, he's quite correct. Pull the plug off of your Vreg and see if that removes the spark.