I am currently transiting in an international airport with four hours to spare, hoping to kill some time by doing some productive work. I take my Macbook (Unibody, late 2008) out and power it on...A white screen appears for a while and then a big question mark folder flashes... I've seen this sign before when I upgraded my HDD. I bought my Macbook 1 week ago, and upgrade two things - RAM and HDD. I got the Apple guys to do the RAM with genuine Apple RAM to 4GB and I bought myself a 500GB WD Scorpio Blue 5400RPM HDD to replace the stock 250GB (I've got too many photos and uncompressed music). The first time I saw this sign in my life was when there was no OS installed on my HDD. Back then it was sensible, but today it is not cause all I did to fix the problem was to reinstall leopard on my new HDD. Fortunately, I had the MacOS Leopard Restore disk in my carry on. I inserted the disc and booted it off from there and it worked. But when I used disk utility, I could only properly see my DVD Drive. The other "drive" was labeled "MEDIA" and this was not my HDD. If it is, then it's not displaying properly. I tried using tools to attempt to acquire disk info, partition info, and first-aid, but all were grayed out. All was going well for a week until today. No problems with my mac. It's my first international trip with a Macbook. I've been using PC Laptops all my life. I'm very new to Macbook environment and I really need help! What can be the cause of this and can this be fixed? I'm quite knowledgeable of PC Hardware and software troubleshooting and if this happened on a PC it may mean: 1. Primary HDD failure...this would mean a new HDD:-( 2. WD HDD suddenly not being recognised by system. If this is the case, how to fix it, and what may be causing it? Not using genuine Apple HDD? 3. XRAY scanner screwed up my HDD...this would be very rare, as most are film-safe. If so, has anyone else experienced this, and how to fix it? I can't even partition my HDD at the moment. It's quite a random concidence that this happened whilst I'm away in transit in an international airport. It is quite annoying as all was going well until today. Any help would be greatly appreciated. Apologize for lengthy post.