1999 monte is not cooperating

I have this 1999 monte and it will not start--I had the battery checked and replaced--the starter replaced--now am going to put in a vats bypass system--how many of these did they make???? this is my second issue with this model--what a pain--car had amp in trunk so took that out--hope this works--what are chances all these fail at once--car acted like vats from the start--diagnosing found the other two--will update when vats put in:confused: