my computer boots up and then it goes to a blue screen that says :The problem seems to be caused by the following file: sptd.sys. and it says i can try to repair it by loading the windows cd and ive tryed that and no sucess and it comes up with a comand promt and i dont know mch about that. then it says to try to start up in safe mode and it wont let me because it says that the sptd.sys file is corrupt or missing. i dont want to have to redue my windows program and lose all of my saved data. what should i do? PLEASE HELP ME!!!