My refurbished Zbook had problems with the screen (it looked like). I called HP, engineer came to my flat few hours later, replaced the screen for a new one. He

My refurbished Zbook had problems with the screen (it looked like). I called HP, engineer came to my flat few hours later, replaced the screen for a new one. He tested it and realized that it's still flickering, so he replaced the GPU. Things worked well, so he left. All of this took ~ 45 minutes. Ah, and it happened in CEE, not in the USA, so it's even more surprising.