The hard drive disappears from desktop and won't boot?

I am working on a iBook G4 800mhz and I'm having a bit of trouble. The hard drive disappears from desktop and won't boot. It will come up occasionally and works fine then wont work. I tried to install the OS again but it disappeared during the install. I am able to boot from the install disc but now the drive doesn't show up. The drive is only a few months old and I am beginning to think that its a firmware issue or just a bad drive.

I am at a loss as to what it can be. A bad drive, controller issue, motherboard????