Hi Etcetera SILC, Welcome to THW.
1. Your motherboard routes the power to components which in turn need power.
2. 5w-10w max only while in use.
3. 10w-15w while reading/writing.
4. VERY LITTLE, depends on what type.
5. Your CPU and GPU are the biggest power users.
Need your full PC specs, parts and models to be more accurate.