When you upgrade the MB, I recommend to do the clean install the OS. If both of MB have the same or similar chipset, you may not need to reinstall the OS.
If you don't want to reinstall the games for steam or origin, you can use the backup feature from them. If you don't want to reinstall the OS, you can use something like IObit uninstaller
http://download.cnet.com/IObit-Uninstaller/3000-2096_4-75161625.html or advanced uninstaller pro to uninstall the drivers, like audio, network, using DDU
http://www.guru3d.com/files-details/display-driver-uninstaller-download.html to uninstall the GPU driver.