With a corrupt bios, the laptop won't boot Windows at all (or any OS), it can't even access the bios menu..Probably a power supply or corrupt CMOS/BIOS.
It could be a psu issue, can't say what to check or fix since it's a laptop, unlike with a desktop pc, you just change the psu..
Or it's the mobo for some reason, though doesn't explain how other components work fine (CPU etc.), but not the fan pin connectors..