How to get a dual monitor set up at home

It is a multi-step (and quite expensive) process, but worked for me:

1. Get a heat pump installed (nowhere near the PC, not even using the same power circuit)
2. Arrive home and start computer, discover no response from screen
1. No power indication
2. No backlight
3. No video
3. Restart computer, thinking screen may be stuck in sleep mode
4. No sign of life from screen
5. Check power and video connection to screen
6. No sign of life from screen
7. Plug screen into different power source (in case bad outlet on UPS), then directly into another wall plug with no UPS or power strip
8. No sign of life from screen
9. Change video cable
10. No sign of life from screen
11. Give up, wonder if power coming back on after heat pump install knocked out the screen. It was sometimes a bit flaky restarting from sleep mode and about 5 years old. As there were no power LEDs or backlight decide it is probably dead.
12. Go shopping,
13. Purchase new screen
14. Plug in new screen and connect video
15. Start computer, no sign of video from NEW screen although power light is on
16. Check video cable, plugs again, no sign of life from NEW screen
17. Restart computer, no sign of life from NEW screen
18. Shut down computer, open case, remove video card and put it back in the same slot
19. Start computer and enjoy crisp clean video on new screen
20. Curious, reconnect old screen to enjoy similarly glorious results on the old screen
21. Find a spare video cable and set up old screen beside new one
22. Enjoy, while feeling slightly mystified, the new dual monitor set-up in the warmth of the new heat pump.