How can I reset my HP Pavilion 550 Desktop

[buzzbuzz24]

I found my grandpa's 2015 HP Pavilion 550 Desktop hidden away and wanted to use it, but there's a problem. I connected the DVI cable correctly, but a window pops up says check video cable. I am also unable to factory reset this desktop. I am new to Hp and windows so if anyone can help me, and explain it simple terms, that would be amazing!

 

[itsmyname]

@buzzbuzz24 --  a window pops up says check video cable. 

Like a TV set that you can tune to multiple channels, your monitor needs to be told which "video-input"  (VGA? DVI? HDMI?) is to be the "active" input. Your monitor is currently "listening" to the "wrong" input.

I am also unable to factory reset this desktop. 

Windows 10 has a "reset my PC" app, to reinstall Windows.

In the "type here to search" area on the bottom-left corner of your screen, type "reset my PC", and then choose from  the list of recommendations.

But, one of your images is a demand to enter a password that probably was known ONLY to to your grandparent.

The "Rules of Participation" for this discussion forum do not allow any registered contributor to help you with this type of "password" issue.

That's all that I am allowed to say.