Information about the hard drive irrelevant. Not only is the bios not recognizing the hard drive, it is also NOT recognizing any other drive!
This appears to be a BIOS(motherboard), power form, or IDE cable failure.
Boot to bios and check your power forms (if the option exists). If the power forms look to be in spec... then you can "possibly" rule out the power supply as being the culprit. I use the word "possibly" because good monitored power does not necessarily mean the power forms are actually getting off the rails and feeding the peripherals.
Standard troubleshooting steps for this kind of failure is to remove all devices connected to the motherboard except one stick of ram (if there is more than one), the video card, the power supply, and your hard drive (with IDE cable connected). No other device should be connected to the motherboard.
If the machine still fails in the above configuration, then the next step is to swap out the above connected hardware, one by one, until all hardware has been "ruled out" as not being problematic. The ram must also be swapped to different ram slots to eliminate possible ram slot problems and, the IDE cable feeding the hard drive should also be swapped out.
If you complete the above steps, and the computer still fails, then you need to seek out a computer repair center and have them analyze your computer. Hopefully you can get lucky and find someone capable of doing this without being too expensive.
I'm going to guess that since your Dell was built in 2001, you don't have Dell support. Even so, you should contact Dell as sometimes they will help you sort things out. Whether or not they'll fix it for free is another question!
ps... I'm glad to see someone finally asked about bios beeps!