Batboard

I'm new to this forum and I need help. I bought a couple of ml900's. Naturally the hard drives had to be replaced as the originals were destroyed. I tried to put in another hard drive, but the ribbon that connects the motherboard and the hard drive apparently doesn't work. I concluded this after testing my friend's laptop (same model). His drive and ribbon boot in my computer. My drive and my ribbon get the same message on his computer as on mine: no hard drive found. His hard drive with my ribbon: no hard drive found. My hard drive and his ribbon: not a problem-the o/s starts to load. What else could it be?

And, if the ribbon is bad, anyone know where I can get another? Motorola wants me to send it in for analysis and charge big bucks.