Ok i thought it was the starter. So i bought 1 from the junk yard; worked for a day. Died again. Bought a brand new one. Never worked. And the technician said the only way to start the car is by directly connecting a cable that connects to the starter(i'm guessing its the power cable for the starter) to the battery. Then it starts. And it does start if i do that. He said it could be the stock nissan security system. Please tell me if anyone had this problem and how they fixed it. Nissan will probably charge me around 1200$!

 

What year is your car? Only the 99's with immobilizer security is prone to problems.
The ignition switch is also a common failure item amoung 4th gens.