did u get a message that said"we appologize for the inconvenience but windows could not start properly..ect"? if u did then you could of selected "Last Know Good Configuration" if that didnt work then move on to the recovery console which is that That MS-DOS screen ur talking about..at the propmt you should have typed this chkdsk /r and it would of most likely repaired the problem if that didnt work then you

should of moved on to a repair installation its simple at the first screen you see where it says press R to repair or ENTER to setup you could of pressed enter then F8 to agree to the EULA then the next screen select R to repair...