Umm... To be honest, I'm not exactly sure about Win8's bootloader, as it's all pretty new to me. If you're not in too much of a rush, I can play around with my GF's laptop (which runs Win8 Pro x64), and see if there's any significant difference. I can't do that right now, but perhaps later in the evening... However, Win 7 is 6.1.x and Win 8 is 6.2.x, and seeing how Vista's (6.0.x) boot method is about the same as the one in Win 7, I suspect that Win 8 has the same bootloader as Win 7.
So. Boot from Hiren's Boot CD (current version = 15.2), select Mini XP or Live 7, and once it loads, you'll have a Windows XP or a Windows 7 desktop. It runs straight from RAM, and makes no alterations to any of your HDDs unless you want it to. There is also a set of tools that is included, containing a partitioning and a BCD editing tool amongst others.
Now, correct me if I'm wrong, but, you have two physical PATA/IDE drives, one of which is labeled as C: and is probably a slave drive, the other one is D: which is intended for storage. If this is so, D: is probably a master drive and so has received the bootloader (Windows dislikes slave drives). This means that there may not be a "hidden" partition on the drive that contains the D: partition, instead, look for a superhidden bootmgr file and Boot folder. Superhidden means you have to set "show hidden files" and uncheck "Hide protected operating system files" in the "View" tab of Folder Options. You can try to see if they're there from your current working system ( booting from D: ), then we'll know what to do next.