@
Bernard.
First off, what are you using this build for? if it's for Gaming only, I suggest you get an Intel Core I7-7700K, it's an absolute beast, if you're looking to game, stream, edit, etc. ( Multitasking basically ) Then a Ryzen is perfect
If you end up getting the Intel, I suggest the GIGABYTE GA-Z270X-Ultra Gaming LGA1151 motherboard
120 GB SSD will never be enough cause you'll put your OS on there, I suggest a minimum 250 GB, Samsung Evo is good
Lastly, the PSU, EVGA SuperNOVA 650 is perfect
And no, if you have Windows 10 on your SSD/HDD, changing the motherboard won't require you to get another copy.