2000 SATURN SL2 WILL/WONT START 5 speed 4 cyl 85,000 miles regulary maintanence

car will/wont start, I found two springs and a black housing/cover on floor board drivers side when my clutch was hanging, I put the rod that connects to the clutch arm back thru the hole it goes thru, car start every time no problem, never put back housing or springs that go under the dash, i think but not sure it a sensor for the clutch!
when the clutch is push it touches the housing/cover that house the springs, the springs are attached to a brass t type clip. but there must be some thing missing as it does not snap together! anyway maybe that is the problem, also my keys are very worn, I got it started took it to my mechanic, try to duplicate the problem and it starts every time, I get home, try to start it, nothing, it is aggrivating not to be able to duplicate this problem when I take it to my mechanic, and I have children and am affraid to go anywere! I can push start it, but then even twice going down hill I could not get it to start, other times by myself got it to start by pushing it?????