would the brain box on 98 buick park ave,cause it not to start

Absolutely. No brain. No start.

There is cluster of wires that ground to the block right near the oil pan. See if the connectors can move. If they can they are probably corroded. Remove the bolt and check all ring connectors for corrosion. Clean all and install bolt. There are probably ten circuits that ground there and if it loose or dirty it could cause starting issues. Does the engine turn over or do you get nothing when you hit the key?