Hi Dallas48,
Congrats on getting a nice machine, I know the feeling of not wanting to wait! :pilotfly:
As for your question, the easiest method without a doubt, is for you to deactivate your 1.5 modules, uninstall from C drive, reboot and re-install to the D drive.
If you wanted to copy and paste it over, it won't work without editing the registry to update your file paths etc. (assuming you're using DCS World directly and not steam)
Now I've mentioned de-activating the modules first, you may not need to do this with a simple re-install provided there are no hardware changes, but I can't be sure as you're installing to a different drive. Hopefully someone else will confirm this.
Regards