UPDATE:
My Nissan Datascan II arrived yesterday, and I registered the key. Works fine. Took the car on 2 short trips. Still worked.
This morning, took the car on a short trip still ok.
This afternoon, I started the car 2x, didn't start. I opened the door the and car started right up. Just a coincidence?
When I got to the mall, I left the car unlocked because I had the car vacuumed and washed. Brought the key with me.
When I got back, started it 3x, it didn't start. I had my laptop with me, so I just registered it again and it started right up.
Such a hassle.
Now, I don't know where to begin troubleshooting from this point on...
Any help would be appreciated.
Another question, what is this box in the picture? That black wire with the white shrink wrap at the base is cut. I'm wondering if it could be related...