It sounds very much like you're using the newfangled Internet Explorer app instead of the more familiar desktop application - if so then that may explain why you're not getting on with it.
Anyhow, to answer your question, at the top of the upload screen where it shows "SkyDrive" there should be little downward-pointing arrow to the right of it. If there is then click on it and you should see the option to browse your computer instead where you can then choose your D: drive.
If you are indeed using the IE app and you don't like it then you may not be aware that there's also a regular version of IE installed already. Go to your Desktop by clicking the appropriate tile on the Start Screen and the IE icon for it may be there or on the Task Bar - if not then post back and I can tell you how to add one.