Hi when I start my pc it is starting and again it is starting from start it showing that safe mode, safe mode with networking , safe mode with command, start windows normally with last working & start windows normally. But when I choose any one from that again it is starting from first so what is the problem? As I am using windows XP.
It means that your windows is crashed. I suggest you to backup all your datas in the hard disk by connecting it to another pc and then reinstall windows in that pc which have crashed.
If you need help post here for further steps.