The 7AP170 has another bay, the question is do you have something in it that you temp remove and install the second drive. Then install the new drive as either the secondary or primary on the other IDE channel. From Windows, format and partition the new hard drive. Now use a cloning program, such as Ghost or whichever you prefer and clone the master drive to your new drive. By the way, 45 Gig to 80 Gig isn't a real big jump these days unless you are going to keep the 45 Gig installed also and yes $19.99 is a good price; so worth it.
3 different OS, so yep I\'m confused.