|1st of all, you mentioned an illegal copy of Windows, so no one should be answering your questions, in fact, your post should be deleted. Regardless, if the OS had been working up until the power problem, I don't see why a BIOS update would suddenly be required?|
2nd, the BIOS comes from the motherboard manufacturer or OEM supplier & is not OS dependent. If you're asking about an IBM, then the IBM website is where you should be looking.
3rd, hopefully you're experienced at BIOS flashing. If you do it incorrectly, you'll be shopping for a new motherboard. Then again, considering you have an outdated P4 & minimal RAM, it may not be a bad idea to just get a newer system, maybe one from say, 2005 or newer?