no start

The Ignition Lock Cylinder failed on my recently purchased 2005 Altima. I replaced the cylinder, however it will not start now. It turns over, but there is no spark. I am assuming I need to either program the key to the ECM or reset the anti-theft system somehow - any advice or help would...

4 days ago I purchased my first foreign car. 2000 nissan Altima with 200k miles. Test drove and it ran perfect. I drove it home, no problems. 2 days later I start it and it made a clank sound when I first turned the key, then ran rough with a miss. I shut off and tried again, it barely started...