Yes Allen, using software such as Acronis is a great way to back-up and restore your PC, especially if you have lots of large programmes installed and important data to protect.
However, the issue of reinstalling an existing OS image onto another platform is a different beast altogether. I would never, for example, take an image of my system running on a series 7 motherboard and then run it on a series 8 motherboard. The differences in the hardware and updated components make this kind of thing a real minefield when it comes to issues of reliability and stability.
Yes, I know, there are plenty of users out there who will say "it works OK for me" but this doesn't really matter. As we always say, no two systems are the same and what works for one most probably won't work for another.
If you are doing a full upgrade of motherboard and CPU the only safe way to go is with a clean install of the OS. That way any problems (and there are always a few with new hardware) can be more easily identified. If you are using a transferred image how can you be sure if it is a genuine hardware problem or corruption in the software due to overwriting drivers? If the install is clean then solving issues becomes a little easier and can normally be solved in a more timely manner.
Another thing to remember is, when changing major components you will also probably have to reactivate Windows if that is your OS. Not so bad if you have the full retail version but not always so easy if you are running an OEM copy.