as title suggests, when i start up my pc it all goes well unitll the windows logo comes up (with the moving loading bar below), then my pc restarts itself (before i get to the login page). does anyone know if this would be a software or hardware problem? and would there be anyway of getting around the problem without re-installing windows or even if it would help? it gives the same result if i to try start in 'safe mode' or try to use 'start from last know working setup' etc. any help would be greatly appreciated. thanks.