Write MBR Code

Question

I am an electrical engineer who has recently discovered the need to modify the code in the MBR. Basically I need the ability to execute code on the HDD before, the OS starts up

Answer 1

Windows has an undocumented utility "debug" which allows to:1) load any sector (including mbr) of hdd to ram. 2)view that code as binary or assemby. 3) Assemble some code in ram.4) write that code to any sector (to mbr also). To start this utilty, type debug at command promt, hit enter. The prompt changes to "-" .then type "help". you get informstion abot how to use it,