Can random code damage your hardware when run in Real Mode? If yes, give some examples how. What happens when the ACPI tables are overwritten? Is it possible to disable the CPU fan through code, and have the CPU overheat and break, or does the BIOS have moron-proof failsafes incase someone would do that?
There was talk, back in the day, about a virus that could damage your monitor. A lot of monitors didn't have any hardware protection against setting a refresh rate higher than they could handle. So if you circumvented Windows (probably Windows 3.1 at the time) and just slammed the VGA register directly, you could run a 60Hz monitor at 120Hz, for example, which could potentially damage the CRT. Yeah, the old "tube" monitors which none of you script kiddies have probably ever seen.