My 2007 cobalt lt wont start or jump start

Sounds like the engine's battery is too low in charge to operate the vehicle properly, or does not have enough power to sustain a load. Have the battery checked for state of charge and capacity. If the battery is low, but not bad - then there could be another problem, such as a charging system failure. If the battery tests good, then there could be some other electrical or starting system problem -- but I'm definitely thinking battery first. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops