It has been awhile since I've posted, but this forum has always been helpful to me, and I have a pretty serious issue, so it's time to post again! I have a mid-2009 model MacBook Pro. 2.53 Core 2 Duo, with an upgraded 320Gb 7200 RPM WD Black hard drive and 8 gigs of RAM. I do a lot of video and photo editing, hence the RAM upgrade, and I'm afraid I might have killed my computer. The other day, I went to boot up, and I got a white screen with a gray folder and question mark flashing in the middle. After doing some research on my phone (that's my only computer), I found out that the issue is most likely caused by either a bad hard drive, or a bad hard drive cable. I got my installation DVD and tried to boot from it and run Disk Utility, but my Hard Drive wasn't showing up. However, I listened to the drive, and could tell that it was spinning just fine. I ordered a new hard drive cable, because I had read that that cable is a wear item, and many people had problems with them failing. The cable came in today, and I replaced it just fine, but I'm still getting the white screen and flashing folder. Just to confirm my suspicions that the drive is still good, I took it out and put it in my friends MBP, which I am typing on right now. The drive is absolutely fine! So my question is, any ideas? I'm afraid that it might be the logic board, which wouldn't be a fun repair to make, and quite costly at that. Thanks in advance.