The macbook pro of mine originall has the 160GB Hitachi hard drive. So I decided to upgrade the hard drive to a 320GB Western Digital (WD3200BEVT) Hard Drive to get a little bit more space. Once I plugged in the new hard drive into my MBP and try to install Snow Leopard, the installation gets stuck (I have been waiting for 4 hours). I also tried with my original Leopard Installation disk that came with my MBP, and still that does not work (does not work as in installation gets stuck). But once I plugged back the original HDD that my MBP originally has and did a complete clean install of Snow Leopard, it seems to do the installation just fine. Does anyone know what I could be doing that is incorrect? FYI: I used the Disk Utility to partition the new drive with GUID as an option and Mac File System Journaled (the first option in the drop down list). I also tried doing Erase on the new drive as well.