Nissan Repair: security system, switch car, altima

Question
I have a 2001 Altima and had to replace the ingintion key and switch. car won't start, I think I need to reset the security system, can you help

Answer
Gene,

The key is going to have to be purchased and cut to the new cylinder.  The key (original) has a code that corresponds to your car.  Take the old key with you to get it matched up for your car and get the new key cut.  It will cost you some bucks since they key is $65 and it has to be programmed to.  Not to mention it has to be cut.  You might be in luck if the new key has the same code as the computer in your car.  You will have to ask.  You should be able to get your old key close enough to the cylinder to get the car to start to enable you to take it in for the process.  The car reads the black part of the key with a reader and if the codes match, when the key is turned the car will start.  If you have the old key you should be able to hold it really close to the cylinder to get it to start.