Ok first you have to check your battery to make sure it is in good shape as well as make sure the terminals are clean. Then check your fuses and relay in your underhood fuse boxes. Yu might try switching the starter relay with another like relay to see if that is good. Also there are 2 250amp fuses near the battery. Make sure those have power going through them. If this doesn't help, then try resetting your security system on your car. If it still won't start then take it to amechanic to see what has gone wrong.