'92 Park Avenue Ultra

Occasionally the vehicle will not start. The dash lights come on, but it will not turn over. Sometimes it will start after a few minutes and not have any problems for quite a while, other times even if left sitting over night it still will not start only to start fine after a few minutes. Could it be the security system? Loose and/or broken wires? The car has over 200k on it and runs fine, when it starts. Also most of the lights on the light monitor dealy located on the ceiling continuously flash. I have no idea where to start on either of these problems and a little help would be appreciated. I saw a couple of similar posts on here with no replies but I figured I'd try posting anyway. If I'm crazy enough to try to fix this thing then someone should be crazy enough to offer up some ideas. I'll be getting the car early next week so I hope to have more information then. I'll repost here with anything else I find and hope someone comes to my aid.

Cut Off The Excess Plastic Over The Postive Battery Cable And Clean The Crap Out Of The Ends! Sounds Like That May Be Your Problem!

my 91 / over 200k was doing a similar with the display board, i made sure the balbs were the right size for each spot and then disconected the neg on battery for 20 sec seems to be ok but one light shows it's out when it's not. they say those displays turn into junk and u will have to replace it as long as it's not your ecm.