回复：在给技术支持打电话以前，可以试试下面的方法

safe mode can not restart laptop.
I delete LSASS.EXE based on online information.
I will try last good registry to restart.
大平洋,problem is that i do not know admin password. my system have a enter window password.
however, is does not work. call dell 技术支持, statement that dell never set a password for repaire tool in system recover CD.
So I do not know who set admin PW? I only created a user account with password at first time.

Thanks for help!

newcomputer