"?" even after hard drive change

At first I think it is a bad SSD hard drive, so I purchase a new one. After installing it, and put the old drive into a USB case, the old drive works like a charm on another mac using USB with which I have recover all the files. The MacBook Air with the "?" issue still blinks. I tried external hard drive, USB CD drive with snow leopard, and even wireless, with no luck. In case of the wireless, I got it to log onto my wireless system, but that is the end of the entire deal. No more next step. Please advice.

Go tit working... finally. It is a bad hard drive cable. After I am able to swap a new cable, the old hard drive is working now. Must have kinked the old one too much that I break it.