I'm trying to install a new hard drive in my Macbook (the last one is broken). I bought a Western Digital 120 GB SATA Notebook Hard Drive. I put it in no problem. I hear it spin up, but the disc isn't recognized when I go to install OS X. It IS recognized in System Profiler as "Intel ICH7-M AHCI", but it's not in Disk Utility. What's going on- what do I do?