If you think your hard drive is about to die, it's time to start thinking about backing up your data. One option is to transfer your critical files over a network to another machine, or burn your data to CD/DVD. Another option, and the best option, is to use a program like Norton Ghost to create an image of your drive. When you get your new drive, just restore the image to your new drive, pop it in your laptop, and you avoid having to individually reinstall all of your programs and restore your data.
One of the posters above is wrong. Hitachi will honor their warranty as long as it is still effective, regardless of whom you bought the drive from. Hitachi just needs to see that the date of manufacture falls within 1 year, and that the drive has not been tampered with.
You don't need to call Hitachi. They have an automated RMA system on their website, hitachigst.com. Just request an RMA, and ship your drive out.
And they do not have a "ship first" policy. You must send your hard drive in to them first, wait about 2 or 3 weeks, and get a replacement drive shipped to you. If you want to be able to use your laptop during this time, your only option is to put another hard drive in it. The original hard drive that came in your laptop should do the trick. If you buy an external 2.5" USB hard drive enclosure, and a drive imaging program like Norton Ghost, you should be able to do a drive-to-drive copy and avoid having to reinstall all of your programs.