I want to repair All-In-One Model #20-c434.

[Myrna9]

Screen will only show lines.

[WAWood]

These All-in-Ones are basically oversized laptops with all the downsides of a laptop (not upgradeable, not easily repaired) with none of the upsides (light weight, battery powered, portable).

Replacing the screen will cost a fortune, even if you can find the part. And then, you have to deal with taking it apart -- and unless you have done the same with lap[tops over the years, you are faced with a VERY difficult task.  These are fragile devices and break very easily.

I tried to replace an HDD with an SDD in one of these two years ago and despite my having done such work on laptops over the decades, and being very careful, I crack the screen trying to get the back off the case.  Since you are replacing the screen, this might not be an issue for you -- but consider that then refastening the case might ALSO crack the screen.

Unlike desktops, these PCs are not designed to be repaired or modified by consumers -- so you risk major damage attempting to work on it.