As for the original question:
Run 'fdisk -l' to see what available disks the system can find. If the disk is there physically, but not shown in the list, then it's either corrupted or unsupported.
You could still use the laptop with a LiveCD, if you do not want to buy another HDD.
As for the new-thread-in-a-thread by 'tester ^ ^':
your /dev/hda3 partition is a logical volume, that's the reason why gparted doesn't deal with it.