Tl;dr Upon powering up the laptop, the power light, screen backlight, and keyboard backlight power on, but nothing otherwise appears on the monitor (no mouse, no boot screen, nothing). I have reason to believe this is not a hardware problem.
Current state of laptop:
- Contains working operating system
- Contains working monitor (at least I believe -- the hardware works, but nothing shows up)
- Contains working BIOS (even though I can't see it on the screen, I believe it works)
Read below for more
- The screen test succeeds (on an XPS laptop, you can test monitor and power functionality when the laptop is off by pressing and holding the power button and "d" key at the same time -- this flashes the entire screen red, then green, then blue, and turns on all lights)
- This problem started after me [unsuccessfully] trying to solve a different monitor related problem:
- The original problem was that, while using an external monitor + laptop monitor in extend mode, the screen kept switching back and forth between each monitor every few seconds.
- To try to solve this, I performed a Windows update and also updated all display drivers. I also updated Dell BIOS drivers
- As a result, I was only able to use the 2nd monitor -- even during boot, the Dell boot logo appeared on the second monitor only. Rebooted multiple times during this process, without any apparent effect on the monitor situation
- It is also worth noting that my laptop monitor is a touchscreen. The touchscreen works (even though the display is only on the external monitor)
- I used
msconfigto cause Windows to boot into safe mode upon restart -- after rebooting, the external monitor was no longer recognized, but neither was the laptop's built in monitor. The boot screen does not show up on the laptop monitor either, so I am dead in the water (as far as I can tell)
- The other bizarre thing is that the original problem (the random switching between monitors) happened on another computer of mine just this morning. But that got resolved simply by restarting and letting Windows update do its thing.
So now this leaves me in a state where I believe that I have a working BIOS + boot screen and operating system, and probably a hardware-wise functioning laptop monitor, but nothing shows up on the monitor, not even the boot screen.
The next thing I am going to try is to boot from a bootable USB stick with Ubuntu (but how can I do this if I can't see the boot screen? enter memorized keystrokes blind during boot?)
Any other ideas how to resolve this?