Goes to grey with apple, then turns off!!HELP!


We have a tangerine ibook and we tried switching my blueberry 6Gb hard drive with it's 3Gb hard drive. We switched and neither computer worked. Switched back, my blueberry works, but the tangerine is shot. It was working before with pulled the switcheroo, but now it goes to the grey apple screen for about 30-45 seconds then it turns off. We are pretty new to mac and used an online manual to take them apart(dumb, I know) So now we are out one computer. Please let me know if there's anything I can I can do to make it work again or if I killed the hard drive. We did install OSX about 3days ago before we did this, took up just about the whole hard drive. Will we even be able to get OS9 to work again??? Please let me know!

Also, I cut the trackpad ribbon(it just kind of severed....) on my blueberry, do I have to replace the whole keyboard or can I purchase just the ribbon?(it looked a little difficult to replace.)