Operatoring system not starting or loading?

Hi,This is Exchange Server forum. For Windows system issue, please write the post in corresponding forum. Windows vista forum:http://social.technet.microsoft.com/forums/en-US/category/windowsvistaitpro/In the new thread, in order to get an efficient help, please let us know what's your system and more detail information (error received, event log error, what have you done before the issue happen, ect...)Thanks,Elvis