Okay I encountered several problems and tried fixing them myself with info from this and other forums. I Bought this macbook on craigslist and it hadn't been reset. 1.First I didn't have the password to install new applications. I couldn't figure anything out but to reinstall the OS and wipe the HD after backing everything up. But stupid me forgot that I need that password to do that. So I tried to boot through the disk by restarting the mac and holding the option key. But there was firmware password set which I also didn't know. 2. Then I thought I'd just remove the HD put it into an external encasing and manually wipe it on a different computer which I did. And then I thought since it's already out and I have access to it and I installed Snow Leopard onto the HD via USB. Then I replaced it back into the the macbook. It then wouldn't boot and stayed on a gray screen. And it kept flashing a folder with a question mark on it. 3. So i tried booting with restarting and the option button held down again. But surprise surprise the firmware password was still in place. Then I figured out away through one of these forums to remove one of the RAM cards and do a reset PRAM thing. Which worked and the password setting was gone, but now it just won't boot at all and keeps telling me to restart the computer. 4. I try a whole bunch of different things. First thing was the option thing again. It gets far enough to show me the HD is there and the install CD is there but when I try to boot through either one it tells me to restart in multiple languages. I tried doing a reset pram again. Try to boot to the CD holding down "C" Try to do a safeboot holding the the shift key. Replacing the memory sticks. I even tried to test it with an extra HD that I know is fuctioning that I have. No luck, anything ends up to the gray screen telling me to restart the computer. I'm now stuck and have no Idea what to do. This has never happened to me before. I also have a macbook pro that I've upgraded the HD and RAM to multiple times and I've never encountered this with that before. I figured I just resetted everything on the macbook what other thing went wrong? I acknowledge something may have gone wrong through taking the computer apart. I've tried replacing everything so I came to a conclusion that there may be something wrong with the logic board which I also came across on other forums. Would it be worth it to buy a new logic board and try to replace it myself? The reason I want to do this myself is because I just read a horror story of someone buying a macbook on craigslist and brining it in for repairs and they took it away because it was stolen merchandise and the guy was out $1700. I didn't spend that much but I don't want it taken away. Any help is greatly appreciated.