About 6 months ago i replaced my HDD with a 500 GB Western Digital Scorpio Blue HDD. Everything worked fine until last night. I was using the computer and it began to hang for a miniute and the screen went grey. I pressed the power button and got the question mark. I tried to repair the drive via disk utlity and it was unable to locate the HDD and partition. i tried mounting it through the terminal and still unsucessful as it cant find it either. I entered Drive Genius 3 and it was also unable to locate the drive. The drive is spinning and not making any unusual noises. I pulled the cover and checked all of the conections on the cable and they are also fine. Resetting the PR and SMF did not solve the problem either.. Any ideas.. I dont have another HDD to test my controller or a external case to test the drive either. My question also, Im still under warrenty, will apple still fix my issue since i replaced the intial drive.