I actually tried this yesterday; I unplugged EVERYTHING, including the ram except for the 1 closest to the CPU, and it still wouldn't boot. I swapped the 1 ram stick with another, and still, nothing. Not being able to access the BIOS was quite gradual. At first, I got BSODs more frequently, then I wasn't able to boot into the OS, and now I can't access the BIOS menu either.
I also got a different BSOD when I tried to do a Windows startup repair after I failed to boot. It read something like Machine Check Exception or something, and I'm unable to get the minidump, as I can't even get into safe mode or anything.