question: individual pieces can be lifted to add or remove (if necessary), sand or mortar.
Capitalize this past sentence correctly.
A: Individual pieces can be lifted to add or remove (if necessary), sand or mortar.

question: if your pc opens the hmi file, but it's the wrong application, you'll need to change your windows registry file association settings. in other words, windows is associating hmi file extensions with the wrong software program.
Capitalize this past sentence correctly.
A: If your PC opens the HMI file, but it's the wrong application, you'll need to change your Windows registry file association settings. In other words, Windows is associating HMI file extensions with the wrong software program.

question: these data sheets are presented in pdf-format.
Capitalize this past sentence correctly.
A: These data sheets are presented in PDF-format.