Ropuchy :
Hello.
Should I reinstall Windows after I change my CPU/Motherboard?
If so, how should I go about doing this?
You should absolutely be prepared to do a full reinstall of the OS and everything else.
There is a small chance it is not needed. But if it IS needed, you'll be much happier if you are prepared for the eventuality.
What OS is this?
If Win 10, read and do this before changing any hardware:
https://support.microsoft.com/en-us/help/20530/windows-10-reactivating-after-hardware-change
http://www.tomshardware.com/forum/id-3164428/windows-build-1607-activation.html
If previous to Win 10, you may even need a whole new OS license.