This is what came to me first. I have unrestricted physical access?

I probably own the machine. If the data on the storage is not encrypted, I own that too.

If I don't want to disassemble anything, I just plug in a liveUSB and it's all mine.

If the BIOS has USB/CD boot disabled? I pull the CMOS battery.

If that fails? The google probably knows the BIOS reset sequence for your board and soon so will I.

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Physical security is important too and FDE is not optional. [Even if you have nothing to hide]