|I would try to access it with a live cd such as knoppix or a barts/ubcd4win disk. If raw then you need to get a more technical disk.|
Any windows boot may damage more files.
It is kind of hard to tell normally. A simple reseat of the cables might work, or replace the hard drive cables. Sometimes the IDE/SATA motherboard chip goes bad on a single channel. Could swap channels to the working channel. You still need a live cd or bootable usb flash.
Could try the hd in another computer too.
A long time ago bios settings could be the issue as the drive was not being reported correctly. It is very unlikey that is the case now.
There are tools like runtime.org and other special disks that can help recover files. You may need to try that also.
"Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10