recently i reinstalled the os on my mac computer and after successful completion, i connected this external lacie hard drive to copy my backup files.

How would the previous sentence be correctly capitalized?
Answer: Recently I reinstalled the OS on my Mac computer and after successful completion, I connected this external LaCie hard drive to copy my backup files.
this page contains information about installing the latest samsung usb keyboard driver downloads using the samsung driver update tool.

How would the previous sentence be correctly capitalized?
Answer: This page contains information about installing the latest Samsung USB Keyboard driver downloads using the Samsung Driver Update Tool.
to a certain degree, you can prevent the rest of the cells from being destroyed by following the advice above.

How would the previous sentence be correctly capitalized?
Answer: To a certain degree, you can prevent the rest of the cells from being destroyed by following the advice above.
the world has started another war.

How would the previous sentence be correctly capitalized?
Answer: The world has started another war.