The BIOS should never make a sound if everything checks out, it's probably complaining about a hardware issue.
One way you could check if the issue is hardware or not is to install a Live CD of some Linux distro and boot from it. If that runs fine, then it's clearly just an issue with the Windows installation. You can then use the Linux system you booted to rescue the files you need from the hard drive, and then reinstall Windows from CD media.
If it's a hardware issue then obviously you just need to replace the computer, or replace the broken part if you can identify it.