Electric~slide anyone? Desperately need advice- Re: continual starting problem

Thanks guys, any suggestions you can send would be most appreciated. You see, I’ve inherited a 92’ Buick LeSabre custom (only my 2nd car ever), and the damned moody thing will occasionally not start. Battery is brand-new. While turning the ignition key one morning and getting absolutley no results (no sounds of any kind) I then had it towed to a local shop. They then told me it was likely an ignition-switch problem (apparently common on this type of car), also mentioned was a computer-chip issue within the ignition. They disassembled it, to make the ‘repair.’ All was well for a few months afterwards, but now I’m having occasional problems in starting (again)… So, I’ve learned that if I open the hood to fiddle with the battery-cables (loosen and then re-tighten them), I can usually and finally get it to start. However, I’ve noticed one odd thing with this: the ‘defrost’ button on my console is illuminated, and has somehow managed to turn itself on. Pretty strange- what’s up with that?? Could there be some other type of ‘computer-chip’ situation I am unaware of going on?? Please guys- any helpful advise you could pass along would really be a appreciated!! Thanks so very much, -Anthony- prefers_jazz@yahoo.com