1995 Cadillac EL Dorado Car will not start at times.

So here is the deal, first off thanks to you guys for providing this forum otherwise a poor guy like myself would never be able to fix his car, so again thank you. So hear is the deal with the car, sometimes (now more often) my car will not start. It turns all the electrical equipment on but the start doesnt engage and its like nothing is happening. I hear the clickin of the solenoid. At first I was baffled completely but some things I have noticed are helping. I have noticed that sometimes when the starter wont engage if I shut the door again the car starts. I was told that something about the orignial Key fob that came with the car could help me with disabling somehting to get the car to start. Is there something with the stock alarm that may be preventing my car from starting? Because it had a cheap python alarm and I decided that may be the problem but now I got a 700 dollar python alarm and the problem is still there. I also noticed with this alrm when I arm it, it beeps back at me and says a door is open? Baffled and confused and would love some help. Thanks very much guys.