How the internet help you solve problem need 7 sentence

Idon understand these and need some ! ?

How can you tell if someone sent you a text message to your email instead of a email

Ihave a singular monitor that is a tv for my computer. recently, i took apart my computer and put it back together. when i put in the hdmi cord and booted the computer to see if it worked, the computer turned on fine but the screen was blue with "hdmi no signal." i've tried everything that doesn't require buying spare parts, any answer is appreciated!