A Chinese AV company discovered a new Trojan, the ” BMW Virus ” (also called Mebromi), that can actually infect a computers BIOS: “It uses the CBROM command-line tool to hook its extension into the BIOS” The next time the system boots, the BIOS extension adds additional code to the hard drive’s master boot record (MBR) in order to infect the winlogon.exe / winnt.exe processes on Windows XP and 2003 / Windows 2000 before Windows boots.
Source: https://thehackernews.com/2011/09/bios-based-virus-discovered-by-chinese.html