95 deville won't start after new thermostat

'95 deville, 3rd owner (2nd was an 70+ yr old, around town driver), low mi. (65000), ran ok, started overheating, replaced thermostat, went to start it and.........Turned over real strong, over and over. Just won't start. :runaround: HELLLLLP

Did you accidentally knock loose one of the connectors to the distributer? If not, I'd check the basics, like fuel pressure and spark. Do any messages come up on the dash, or is the SES light on?
Also, is this a Sedan Deville with the 4.9 liter engine or the Deville Concours with the Northstar?