HD not showing in explorer

My main HD has just crapped out on me (thanks to toddlers that have cut power to my computer in the middle of many different occasions). I can barely get it to boot up to my XP Pro log on screen, and when I try to log in, it will go no farther. I put XP on another HD, and set my old HD as a slave in an attempt to recover files and maybe fix it. The old HD will show up on my device manager, and shows it being a "healthy, active" HD, but it does not show in explorer. What's wrong? What do I do?

 

As far as I know, the Windows Device Manager interrogates the hardware in the hard drive, but does not look at the data structures on the hard disk. Windows Explorer won't see the drive if it is incorrectly formatted, has a format that Windows does not recognise, or if the system areas of the drive have been corrupted.

I'd start by going to the drive manufacturer's site and downloading whatever diagnostic utilities the manufacturer provides for that drive. Some of them will report on the validity of the formatting/partition tables/master boot record, etc. as well as the integrity of the hardware. It's possible that some of the system areas have been corrupted, with the result that Windows Explorer can't read the drive.

Perhaps someone else can recommend a diagnostic that will check on the validity of the data structures on the drive. There may be something that can be downloaded from MG's Files section of this site.