To begin, I have an idea but am unsure how to implement it. I want to set up my 'puter so that during boot a fake bios screen or whatever appears. "FBI Field Computer 4, Now Connecting To FBI Mainframe, Location Detection On, GPS Enabled, Camera on, Current User Photo Uploaded, Triangulating Complete, etc etc."
There's a few ways to do that.
If a static image will do, you can change the Windows boot logo as you're already looking into. You could also possibly mod the EFI firmware to change the BIOS boot logo (what Windows is actually showing you on an OEM system). Most EFI firmwares come from one of a handful of companies that develop them, such as AMI, and modding is usually accomplished by vendor-specific firmware hacking tools. I'm assuming if you're concerned with it being stolen by a tweaker, that we're talking about a laptop. Many laptops actually won't let you flash a modified firmware. Some manufacturers do provide an official utility to change the graphic displayed on bootup though. Lenovo offers one, complete with instructions, that actually doesn't work because it's fatally broken and the chinks don't wanna fix it.
If you want something animated, like in the vain of those fake and gay progress bars you see on tax efile sites ("we're checking your return for errors, 43% done") it will be significantly more involved.
You could write an EFI executable and tell your computer to run it on boot, and for what is probably a few dozen lines of code and some uncompressed or RLE bitmap graphics you could have something convincing that runs every boot. After it's done doing the fake FBI shit you simply have it chainload the Windows bootloader or call the EFI firmware to boot next-in-order.
You could hack the source code of the GRUB bootloader (of Linux fame) to show the relevant things on-screen, and then configure GRUB to chainload the Windows bootloader, though I'm not sure this is going to be any less effort than writing something from scratch.
You could write a kernel mode driver for Windows to show whatever you want on the screen while WIndows is booting, but this is even more work and way more janky, and it might cause Windows to freak out. Also, it would only have the desired effect after all drivers are loaded and the kernel actually starts to execute them.
You could render the FBI concept to a video and then have a video player program run fullscreen during the winlogon phase of the Windows bootup process. I'm pretty sure there's still a way to do this on modern-day Windows. This is probably the lowest barrier to entry method.
Basically in the event I get jacked, I want to spook whatever tweaker does it. Also, is there a way I could set things up so my 'puter gets completely bricked if someone tampers with it? I always remove the serial numbers from my things so they can't be pawned but I want to take the preemptive spite up a notch or two. General suggestions not directly related to my question are also welcome. Thank you for your time, patience and consideration
Best thing you can do is set passwords. Start with the system password in the BIOS, which on most laptops is extremely difficult to reset. Set the option to require the password to boot. Without the password the machine is effectively a brick.
Every laptop I've ever seen from about 1998 onward implements ATA Security. This is usually exposed as "HDD password" or something on the same screen where the system password is set. This does not encrypt the drive and also does not degrade performance, rather what it does is cause the drive to power up in a locked state and remain locked and to not allow any access until the correct password is sent. Without the password, the SSD is a brick. A side effect of this is that because most desktop firmwares do not implement ATA Security, a drive with a password set will not function in a desktop computer even if you know the password. A drive with a password set that is not unlocked is invisible to the operating system, as well.
These two things together essentially reduce the value of the computer to "parts only" with two major parts themselves already being reduced to salvage value. I highly doubt a tweaker is going to sucessfully fence such a computer, and trying to hawk it on Marketplace or eBay is probably too much time and effort. That of course will not prevent the theft, but the zero percent chance of recovery becomes nonzero because you might get lucky and happen across it after the tweaker inevitably ditches it.
It should be noted as well that all of the above FBI fakery methods would not be visible because any of those methods (with the exception of the BIOS boot logo hack) will not show until after correct passwords are entered.
