Many motherboards allow the BIOS logo to be disabled or replaced. I had the option of doing it to a dell bios in an arcade cabinet I'm building using a bios editing tool. I believe it works with most Inspiron and Latitude systems.
Here's some guides on removing all the visual elements of Windows 7 and 10 so the boot to your frontend is invisible (Steam Big Picture, Launchbox, Retroarch, MAMEUI, etc)
Windows 7Windows 10^I haven't actually fully tested these guides as I haven't fully finished any of the WIP arcade cabinets I'm working on, tho I've seen videos of the setup working perfectly.
Powering a PC on remotely from a game controller is something I've never thought of doing. I generally leave my computers on all the time, and they remotely turn my screens on when a button is pushed, but A quick google search turned this up:
SilverStone ES02-USBI know most motherboards can also be turned on from network with the right bios setting, tho to make a controller do this might require some other hardware - arduino based or something to intercept the signal and send the network boot command.
I used to run my XP machine completely from a controller while gaming, tho this was through a frankencontroller:
It's a PS2 controller with a USB keyboard cable coming out as well. I ran a program that allowed the right analog and shoulder buttons to control the mouse, and with that I could relatively easily control windows enough to switch games, navigate webpages and other tasks without needing a full sized keyboard or mouse.
Most laptops have a configuration for how windows behaves when the screen is closed. I generally set mine to simply turn off the screen so I can operate it from a distance with 2.4ghz full-sized keyboard and mouse through HDMI to a better screen and audio to my bose dock (this is how I set up my hotel room when I'm out of town for work)