the principle of "guardian spirits" is a universal principle.

How would the previous sentence be correctly capitalized?
Answer: The principle of "guardian spirits" is a universal principle.
if your pc opens the pds file, but it's the wrong application, you'll need to change your windows registry file association settings. in other words, windows is associating pds file extensions with the wrong software program.

How would the previous sentence be correctly capitalized?
Answer: If your PC opens the PDS file, but it's the wrong application, you'll need to change your Windows registry file association settings. In other words, Windows is associating PDS file extensions with the wrong software program.
on either side of god’s throne was a super archangel, a cherub, whose wings stretched out covering the very throne of god.

How would the previous sentence be correctly capitalized?
Answer: On either side of God’s throne was a super archangel, a cherub, whose wings stretched out covering the very throne of God.
supplied with integrated quick connectors and fixed end brackets

How would the previous sentence be correctly capitalized?
Answer: Supplied with integrated quick connectors and fixed end brackets