Question: 3) what are the minimum requirements of windows 10 and how to install it?
Answer: Latest OS: Make sure you're running the latest version—either Windows 7 SP1 or Windows 8.1 Update. ... 
Processor: 1 gigahertz (GHz) or faster processor or SoC.
RAM: 1 gigabyte (GB) for 32-bit or 2 GB for 64-bit.
Hard disk space: 16 GB for 32-bit OS or 20 GB for 64-bit OS.
Graphics card: DirectX 9 or later with WDDM 1.0 driver.