I would bet that your 80gb C:\ drive is where your default 'park or download drive. With that being stated. You can move all your files to your E:\ drive. However be aware when you open software it may give you the bonk sound of Windows cannot find your file or it is missing. You will need to redirect the software to your E;\ drive when that happens.
Furthermore, you wont be able to drag programs to your E:\drive only the file folders. It is not recommended to install programs on 'other drives' then your C:\ drive anyhow.
To address your question after that being stated. Open your Computer, burrow down until you see you drives C;
Open your C drive Folder then minimize it, then open your E:\ drive Folder. Open the windows so you can see them both open (resize them) inside the C drive folder Cntl A and then drag it over to the D drive folder where you want the folders. And go make a sandwich cause it is going to take a minute.