HP desk top- get blue lines through screen

[MarkM20]

blue Lines on screen and 

[WAWood]

This is almost certainly an indication of failing video hardware -- either the screen or the video chip or both.

You need to connect an external monitor to the All-in-One.

If the visual artifacts also appear on the monitor, then it is a failing video chip and since those are soldered to the motherboard, they are not replaceable.

If the visual artifacts do NOT appear on the monitor, then it is a failing video screen.

We are not able, or permitted, to provide any repair estimates or equipment prices.

If the All-in-One is still under warranty, you would need to contact an HP Repair or Service Center.

Since you live in the U.S., here is a link to the HP Service Repair Centers:

https://www.service-center-locator.com/hp-hewlett-packard/hp-hewlett-packard-service-center.htm

If the All-in-One is no longer under warranty, then your most practical "solution" is to replace it. Why? Because most places will not work on All-in-Ones because replacing a screen carries with it a major risk of damaging it and its replacement because the screen has to be PRIED off, and the new one PRESSED on -- and both of these can easily crack the screen.

Good Luck