What version of OS X are you trying to load?
I recently inherited a Pismo, 400 mhz and a 6gb hard drive. Other than the tiny hard drive, the computer is in great shape and has a lot of service left in it. I was able to load Tiger on it, and it's working fine. I replaced the hard drive with a 100gb Seagate, but when I tried to format the disk,the new hard drive didn't show up during installation attempts. However, the volume was visible in the system profiler and the disk utility...I reinstalled the original hard drive, and that booted successfully so I guess that means I didn't damage the hard drive cable, which I had feared.
Does anyone have an idea about this? So odd that that I could locate the drive in the disk utility but not at the installation screen.
Well, thanks in advance for any help you can offer.