09 Pontiac GT G6 Electrical Problem

My Pontiac G6 had not had a single issue in
six months until i went to the gas station. My
dad checked my oil and noticed i was low.
Also my left head light went out for probably
the third time since i have had this car. We
usually replace this tiny wire an the bulb
wich you can get at autozone. But today
when my dad shut the hood my car would
not start. We checked battery connection
then the relays. We found a relay just laying
in the grooves under the hood and thought
"what the heck how did this get here"? We
replaced teither the cool/fan fuse or the
start fuse with the random one we found.
Nothing happend. Then my dad proceeds to
push down on all the relays and the relay
box. It started up. Mind you this car has died
randomly in our driveway from me coming
home. We have replaced the starter and had
a mechanic rewire the starter wires. We
have messed around with relays and
checked the battery. Seems like a
connection somwhere. Headlight still does
not work but neither does the car turn over.
My dash lights come on but no crank. Help!