Just a quick post to show you how to run a Lenovo ThinkServer TS140 Server in a headless configuration, meaning that it runs without requiring a monitor, keyboard or mouse to be plugged in.
By default, the TS140 Server does require at least a keyboard to be plugged in during boot up. If not, the boot process will display errors during POST.
In order to run Keyboardless Operation, boot into the BIOS by pressing F1 and then going to the Startup section:
Scroll down to Keyboardless Operation and then hit enter and select Enabled in the menu. You will then see that it changes the setting to Enabled, per the below:
Hit F10 to Save and Exit and from this point your server can operate in a fully headless configuration (assuming you do not have a monitor or mouse plugged in either).