Not entirely sure what you've done.
It rather sounds like you had Windows 7 installed on C, with the programs on D and you then did a clean install of Win8 on C.
That being the case, then you won't be able to use the programs installed previously (under Win7) on D. Some may work (after a fashion), but you cannot rely on it at all.
When you install programs all sorts of information relating to the programs is effectively stored with the OS. Having done a clean install of Win8 will mean that your OS does not know of the programs on D.
If you can restore your original Win7 set-up, I'd recommend doing an UPGRADE to Win8, not a clean install. Alternatively re-install all of the programs again (if you have the installers etc.).