I want to know if a laptop or a desktop have been booted from an external device. Are there persistent BIOS logs or some other method to use for that purpose?
If your boot drive of a normal PC is formatted with UEFI/GPT, every time it is powered up a small file is rewritten, and the previous versions of that file are preserved. You can explore the BIOS/firmware with UEFItool to look for date and time stamps of those files.
You can learn if the drive is UEFI/GPT or MBR/BIOS in Windows with this app.
However, that depends on how standardized the BIOS is, for a manufacturer can use a custom BIOS which prevents this method, which is why I asked.
I do not know if there's an MBR/BIOS specific method.