I recently replaced my Mac standard HD with a western digital, worked perfect for ~3 months. Last night I got a flashing ? On boot. I tried recovery and disk utility but my disk isn't showing up at all. I ordered a replacement data cable to try that before I go broke in the apple repair shop. My question is : is it worth my time replacing it myself? Is it likely this is a sata issue or is it more likely a hard drive problem? Unfortunately I don't have another hard drive to check.