It WAS plain stupidity. I installed the OS and everything went well. It was working perfectly fine last night and this morning, but now it's all screwed up. It won't start up. Instead it beeps three times and then the LED blinks four times, over and over. From other posts that I've read I guess it has something to do with the RAM, but who knows. I got this ibook for free becasue it had a busted hard drive, but now after putting in a new one, I don't know what's wrong!?! Is it me or is it the damn machine. Should I bite the bullet and take into an Apple Store to see if it is worth fixing?