Contact the vendor of your particular drive for help, you can't just pick a vendor and ask, they only will support their product. If the warranty seal has been removed, you probably won't get any help with replacing the drive though. How does the drive not work? Does it spin butthe BIOS and/or Windows can't see it? Making noises?
Not the warranty seal but the "Vaccum Seal", the one at the top and the side of Seagate 7200 HDD, a round foil like seal.