What I use at work is a commercial/server copy of Acronis ... you can create a bootable CD with it and from that you can create an Image of your hard drive and store it elsewhere, such as on another hard drive. I don't know of anything that's free that you can do this with but no doubt there's something out there. An Image is exactly that and with it you can completely restore your system to the state it was in when you took the Image including all software, files, folders, and the OS. With our version of Acronis you can even restore an image to dissimilar hardware.
If you can't find anything, use Win7's backup utility and make a full backup of your C: drive onto one of your other drives that has the most room.