tl;dr: How do I program a key that is cut but the car was reprogrammed for a new(uglier) key?

Long version:
Hello all, I've had this issue since I bought my car but I never thought to do anything about it, but anyways, when I bought the car it came with 3 keys. The reason for all they keys is because apparently the previous owner lost the keys, made new ones, then found the old ones, not bothering to re-program the old ones. They are all cut the same way, and all of the remotes work.

Keys:
1 Original Infiniti key (Does not start car)
1 Aftermarket Key (Starts car, but alarm goes off when put in door)
1 Another aftermarket Key (Does not start car)
I'm not sure about the doors for the keys that don't start the car because I haven't tried. And when I say does not start car, I mean it goes in and cranks, but no ignition.

But, is it possible for me to reprogram the key myself? I found this link, which I haven't tried yet, but it sounds like that is how to program a remote, rather than a key. And it's for a different car so that could be problematic anyways.

Getting a dealer to do it isn't worth the price considering that I do have a key that works, it's just not the one I would like to look at.

 

You can program the key fob/remote to open the doors easily by yourself.

You cannot program the chip in the key to start the car yourself, it requires special software that sells for a few grand.

Buy an OEM key off eBay(think I paid $30 for key and fob), have the dealer cut and program it... cost me $50. When I talked to the parts guy he actually said he'd do it for free... but when I got there the service adviser said he had to charge me. Maybe you'll get lucky.

I actually had it done at a Nissan dealer because there is no Infiniti dealer close by.

$80 isn't that ridiculous considering the dealer wanted to charge me like $120 for a key and $80 for a remote plus the cutting/programming fee.

 

Try going to a good locksmith. I bought a second key on Ebay and had it programmed at a locksmith for $40.

 

The dealership was asking $178 for the part ( new key) plus $118 to program it plus labour ( 1hour) plus tax.
After signing on to this amazing website and reading the different forums, I got great advise to call a local lock smith.
20 minutes and $85 plus tax later, I have a new programmed key for my car.
Thank you.
FYI: action locksmith 416.261.1422