I have recently upgraded my system from windows vista to windows 7. I attempted to boot into safe mode on the way to uninstall a application that was worrying. The laptop loads driver but stop at classpnp.sys as well as the log on screen come into view. At this moment the laptop instantaneously reboots into usual start up. How can I resolve this, if I ever require safe mode I will have a real problem. I did not understand what the cause for this trouble is. If you have any suggestion regarding to this trouble please let me know. Your suggestion would be appreciated.