My Lenovo W520's internal port to the internal screen is dead, but I would like to use it as a server and it would be useful as such if I could install another operating system on it. that is hard when by default it uses a screen that I cannot see. so I am wondering if anyone has a w520 (or t520 I believe) and can walk me through the bios to turn off the internal screen.
Most laptops will sense a closed lid and, when you reboot/power-on, will output video to an external monitor if connected. That includes the initial BIOS display. Note that the BIOS display time may be so short you won't see it, in which case just keep pressing
F1 repeatedly as soon as you power-on.
Now for the bad news. There is no setting in the BIOS that can disable the internal screen. You're stuck with using the laptop closed, at least while you prepare and install the OS (you'll need a USB keyboard and mouse).
Once you've installed the OS, you should be able to configure the OS' primary display to your external monitor and, thereafter, you may be able to use the laptop's keyboard and trackpad.
With the Thinkpad T4502s, you can at least set the default
boot display device:
and there choose for example
analog, which could solve your problem?