Personally i would just get new memory rather than using slower memory that's just kicking about. Even if you just started with a new 8GB Kit.
I'd also agree with @Turtle Rig and get an SSD. Couped with an HDD It's worth it for the long run.
I would also recommend going for a Ryzen 3 2200G over the 1200 as it will only be like an extra £20.
I would also conisder upgrading your RAM to atleast 2600Mhz as Ryzen works better with faster memory.
Your CMOS battery is more than likely dead.
Pop it out and change it over and see if that fixes it.
Bare in mind when you do change it the system will cycle twice for the fresh battery.
Then it shouldn't do it again.
Well did you look at the specs of your motherboard?
It only has 2 chassis fan headers so you're going to be putting 6 fans onto 2 headers.
Not counting the fan header for your CPU.