Where are you working, and what kind of power supply are you using?
The Raspberry Pi is very finicky about voltage, and it’s possible that these problems are all caused by insufficient power. I started working on mine while living in a 100+ year old house with ancient wiring. I had trouble getting it to detect keyboards, mice, controllers, etc, and it even affected installation of the setup script.
First, try replacing the power supply with the one for your cell phone charger (make sure it’s listed as 5v 1a first). The acceptable margin for error in those things is wider than what the Raspberry Pi can handle, so try a few.
Otherwise, try moving your workspace to a place with more consistent electricity.