A few questions regarding replacing a motherboard:
1. Do I remove all devices in the Device Manager?
2. Do I need to manually install the software for all my drivers (both old and new)?
3. Should I do a clean install with a new OS?
Why are you replacing your motherboard?
If, for example, you are replacing a faulty P67 B1 motherboard with the same B3 version, you don't have to do anything.
You will get a request from windows to reactivate since it looks like a different motherboard.