I'm new to this forum so my apologies if this topic has already been discussed. I searched for related threads, but didn't find anything. I am in the process of upgrading my mid-2009 13" MacBook Pro's hard drive. After reading instructions, many posts, and loads of other information, I selected a WD Scorpio Blue 500GB HDD. Prior to installing it, I performed a Time Machine backup on my external hard drive. My intention was to boot from my OS X install disc and then restore from Time Machine. (Of note, I don't have the original boot disc available to me, but instead have a OS X 10.5.5; I'm running 10.5.8. A friend told me this wouldn't be a problem. I mention this in case he wasn't correct.) After installing the new HDD, I turned my computer on. I waited until seeing a folder with a question mark to insert the OS X install disc. After inserting the disc, the Apple logo appeared, and shortly afterward the winding "gear" image appeared. After up to 20 seconds, the screen went black. I tried doing the same thing a few times, and also tested pressing the C button upon startup. Upon each attempt to boot from the OS X disc, regardless of whether I pressed "C" while it loaded (also tested pressing C at different times during the loading process), the "gear" image continued until the screen went black. So, that's my problem. I try to boot from the OS X install disc only to ultimately get a black screen. In case it's helpful, each time the screen went black, the HDD continued to run for a short time. Eventually it would stop and then restart again. Does anyone have any suggestions?