I have replaced everything. I may as well build a second G73SW. If I connect the ribbon for the hard drive ports to the motherboard, nothing starts at all. I have replaced the hard drive port. I have tried removing the SSD and replacing the motherboard, CPU, and RAM. The blue light on the motherboard blinks very briefly, but nothing else shows any sign of life. If I unplug the SATA ribbon from the motherboard though, the system starts and asks me to insert boot media. I can run the system on Kali linux from a live usb and the DVD drive starts. I'm at my wits end.
A 2½" hard drive will need two connections; one for data which is the wider of the two and the other is for power. The data one will come from a different part of the motherboard than the other. The power one is usually a 90° stubby little plastic and is half the width than the other.