Imb thinkpad indow problem

Hi just a few things need to know is this a new hhd you are using have you changed the hhd on what the code means is you will have to reformat hhd and reinstall but before you do this i would like some moor info was it working ok before have you just installed and this is the problem there can be al sorts of problems why it wont boot but at the end off the day it ends up reinstalling what os are you using /vista/xp