What does having a black monitor have to do with it? Your problem is
installing too many security updates at the same time. Now, you can't tell
which update caused the problem. One or two updates at a time is a much
safer way to go.

You will probably have to reformat and reinstall the OS if you cannot get
into safe mode to try to remove some of the updates. Some of the security
updates cannot be removed and if one of those is causing the problem, you
will definitely have to reformat and reinstall.