If your drives are the same size, the built in for windows works great. If they are different sizes then you'll need something aftermarket.
Start button, do a search for Back up, the first one should be Back up and Restore. Open it, left side of that window has 2 options
Create a System Image and Create a System Repair Disc. Create System Image is what you want.
When you click it, it will be looking for something to back up to. I used an external USB hard drive for the image.
I also went ahead and made a new repair disc as well.
Swapped out the hard drives when all that was done. When you boot up with the repair disc in and the externel drive plugged in, the onscreen guides you through the rest, from what I remeber. It took about 45 minutes and everything was installed and working, and not required to re-activate windows.