Yes... any time you go to a new motherboard, it is highly recommended doing a fresh install of the OS.
Sorry, but I disagree. Unless you run into serious stability problems that you can't resolve easily and in a timely manner, you can use your existing installation.
Just boot normally and install the necessary drivers as Windows is asking you during startup. You may need a few restarts, but it should all be ok in the end.
The only caveat may be that you probably need to re-activate your Windows. It will detect a major hardware change and will ask you to re-activate.