Windows 7: Moving/reinstalling files between hard-drives on a dual-core laptop

So, I've got a dual-core laptop (I can post my specs, although I've got them on my account, aswell) and it's the first I've ever had. Before this laptop I used to just use single hard-drive pcs and was fine with it.

Basically, I've only really installed everything onto one single hard-drive on this laptop, so one is full whilst the other is basically empty. It wasn't intentional, I just wasn't aware that I had another hard-drive to install onto.

However, I believe this can cause my pc to slow down a little, so I was wondering if it's possible to move files from one hard-drive to another. I'm thinking of just putting my games and music in one hard-drive because that's usually what gets accessed the most.

Would this be possible? And, would it decrease the strain on my pc's CPU, letting it run smoother?