Boot from a boot disk.

You may want to enter bios to see what it says about the harddrive. (it is
possible that the harddrive is not listed because of the cmos battery is
dead).

If this is not the case then use Fdisk /status and see if the drive is
recognized and there is a valid partition.

If not you will have to partition the drive (fdisk) , format the drive and
install an operating system.

Please visit the web site of the laptop manufacturer since you may need
special drivers etc.