This is tough without knowing exactly what "went wrong" in the original process. Since the remote I-Key functions were working before they tried to program the new fob, I very much doubt the I-Key Unit went south just because someone tried to program it. The first thing you should do is go through every fuse in the fuse box with a test light, but if they're good, there are a few "kinks" that can occur in programming on older I-Key vehicles. One is that the center antenna under the console must work or the programming process won't complete. Even though there are other antennas in the car, the system won't use them for programming, it will only use the center one. They should run an antenna diag on the car to find out. The I-Key Unit won't throw codes for a bad antenna until a diag is executed, there's a specific procedure for it in BCM Work Support. Secondly, the order in which keys are registered matters on some of the older models. To be safe, old keys must be re-registered first and then new keys added, otherwise older keys can become unusable. Since your oldest key still starts the car, I don't think that's your problem here. Lastly, BCM's and IKU's are known to occasionally get "stuck" in key-programming mode because of a key that won't read. Your China key may have an issue that caused the system to hang. Try disconnecting your battery negative for 10 seconds, then put the new Infiniti key in the doghouse after reconnecting and press the start button, see if you get 5 flashes from the security lamp. If so, put your "good" key in and repeat the procedure, it should un-hang and both keys should begin working.