The drive has either failed or been disconnected. It's one of three things;
1. Your hard drive controller has failed.
2. Your Hard drive has failed.
3. The connection between your drive and motherboard is bad.

If it's 1, you're pretty much out of luck.
If it's 2, you'd need a new hard drive.
If it's 3, you're either able to replace the cord (warning, most laptops don't actually have a cord, but rather a direct socket. I'm not sure about this model) or you're going to be referred to option 1 or 2.

If you're doing this as a "project", go for it. It could be fun to play with it and hopefully get it restored, but keep in mind this is not a useful computer. It wont run anything but Linux (streamlined distribution at that) or XP (very slowly). The system is pretty dated you wont be losing anything since you haven't seen it in years anyway.