EDIT, could I just copy/paste the 'Program Files' and 'Users' folder to the D drive and delete them from C?
For games,
NO, you cannot. Copying a game like any other document or picture is a pain in the ***, you need to manually (or maybe there's a program I've not heard of) change the registry keys to correspond with the new location yadda yadda.
Not only that, many ingame files are written to correspond with the desired location. So those games would require you to mod them in order for the "desired path" to be correct.
Also, that D:/ should be D:\, as the former would give a totally different result compared to the latter.
There are some good news though. When installing
any game nowadays, you're given the option to choose the desired install directory.
I.e. "Where do you wish to install the game?" or "Please choose the desired folder for the game to be installed in", simply choose a folder created in the D:\ partition, (like "D:\Program Files\") and the game will be installed in the D:\ partition!
But there is a big 'but'. Windows 7 64 bit (Windows 6.1) can almost always only run 32-bit applications (like older games, pre-2007) if the games are being installed in the "C:\Program Files (x86)\" folder, as this presumably tells the OS that this application is supposed to be run in 32-bit mode.
So for future reference, choose to install games in the D:\ directory if you desire, but 'copy/paste'-ing a game is no easy task, even for professionals.
Edit:
You're saying that changing the desired path directory from C:\ to D:\ did not work when installing a game?
There are several thinkable reasons.
1. Did you write 'D:\' or 'D:/', because those are completely different. Only the D:\ should work (unless Windows uses aliases like Linux, but I'm unaware of that).
2. Having multiple sub-folders that does not exist when trying to install a game will cause some confusion.
You mentioed that you have no games installed on the D:\ partition, then you probably do not have the 'path': "D:\Program Files\" or "D:\Programs". So installing a game in "D:\Program Files\Somegamecompany\Somegamename" will cause a lot of confusion as not even the 'root folder', "D:\Program Files\" exists.
It can be manually created though. But this is not a guarantee that the game will work, it might be 32-bit based, or the default desired path might be different (it might be C:\Programs\ for instance).
Sorry if I'm making it sound complicated, because it's not, doing all these things is easy, really
.