Chosen Solution

How can I open in safe mode

Your User profile may have been corrupted, although the operating system should have been able to authenticate you and create a temporary profile. You will need to know the administrator password to fix this problem, you can try to sign in as administrator without a password (older versions of Windows defaulted to a blank password, newer versions do not). If you do not have the administrator password then you can try to download a Barts Ultimate CD and make a bootable USB drive to change the password. The other option is to remove the hard drive or SSD and copy the data to another computer using an external drive adapter, then reinstall the operating system, drivers and applications.