First, check the manufacture's website for a diagnostic program. Run it on the bad drive, and write down the error code it gives you. Then call em up via the 1-800 number on their site, Tell them your drive is bad, and give them the error code when they ask (they'll also need to verify it's under warrenty, so you might want to pull it out so you can give them the numbers they ask for from the drive). Ask for them to cross ship you a new one, because it's an important PC. You'll need to give them a CC number (which they won't charge if you ship the dead drive back). A couple days later, when the new drive comes, put the old drive in the box, and ship it out via UPS or FedEx (just make sure you get a tracking number).