BMW Repair: 1999 323i will not start, starter solenoid, battery cables

Question
my car did this a few months back,it wouldnt start .some times i got a klick,sometimes not.i mest with the funky set up in trunck of car.the part that connects to battery ,it is prest into the connector.it had come loose.well car is doing same thing now but connection is good.i have put in a new starter@altenator.there is 12 plus volts to starter ,still it doesnt start even with a jumper on it.i disconnected the cluch switches on back of pedal thinking they may be bad,that didnt help.anything you can suggest to trouble shoot i would appreciate.

Answer
Brady, does the starter solenoid make that clicking noise when trying to crank the engine now? What is the voltage at the battery voltage? What does the year stamp show on the top of the negative battery terminal? What happens if you charge the battery? Are your battery cables clean and tight? If the engine doesn't crank and your battery is good with over 12.45 volts then try another vehicle key. If you are getting the solenoid click then the batrery voltage is too low.
-Evan