Is this a hard drive that has been in this PC for a while or a new one you just put in? If it has been in there and you believe it has data on it you want, do not format the drive, as this will wipe out your data.
If this is a HD with data to be saved, let's eliminate physical failure, 'cause cloning or full imaging probably will not even start. Are there any strange or unusual noises or behaviors coming from the HD as BIOS and OS attempts to read it?