lsass.exe-application error

hey im having this problem,i start up my computer and it loads fine until the user page is supposed to come up...i get the lsass.exe - Application Error and in the box it reads the application failed to initialize properly (0xc0000005).click OK to terminate the application. i hit ok twice and it goes to a black screen with a movable curser...now im on my wifes laptop and i am wondering how can i solve this problem...i have my operating system Reinstallation DVD but how do i use it if i cant get onto windows