Spent a few hours chasing down a problem with my office computer last night. It’s just remarkable how many ways our computers can go wrong, isn’t it? Honest, I would gladly give up much of my job security if it meant our technology would work more reliably.

The symptom: the computer starts up and presents a login screen; when the name and password is entered, the screen goes black and stays black, with nothing except a mouse cursor that moves around quite happily. Lots of hard drive activity as if the system is starting normally.

It wasn’t the first time this had happened but it never lasted long before. It happened once or twice while I was working on the problem I described here. I thought I had resolved it. Not!

Shut down, restart. Cross my fingers while restarting. Turn the monitor off and on.

Hit Ctrl-Alt-Del and the screen immediately appears with the options to lock the computer/log off/change password and “Start Task Manager.” That would be good, eh? Try and start Task Manager but oops – right back to the black screen. If I log off, the login screen appears right away, fully lit up. The screen is only black when I log in.

Log in to other accounts – black screen, moving cursor.

A little Googling and imagine my surprise – people have experienced the same problem, plus variations on the problem, and there’s no consensus on what causes it or how to solve it. I don’t have all the links – I’ll just give you the flavor.


  • Windows doesn’t start; computer displays black screen with blinking cursor
  • Windows starts but login screen doesn’t appear; mouse cursor moves around.
  • Windows starts and login screen appears; screen goes black after logging in on some user accounts but not others; mouse cursor moves around.
  • Windows starts and login screen appears; screen goes black after logging in to any user account; mouse cursor moves around.
  • Some people have seen this after returning from sleep or hibernation; others after remote desktop sessions; others (like mine) have no connection to anything in particular.

Possible solutions:

  • Disable all Cyberlink programs (makers of PowerDVD) from starting automatically.
  • Disable LSASS.SYS (deep part of Windows responsible for some networking functions) from starting automatically.
  • Disable [fill in the blank] from starting automatically.
  • Remove NTUSER.DAT from the user profile after logging into a different administrator account and let it rebuild on the next login.
  • Bring up Task Manager and restart Explorer.exe.
  • Change video card settings for multiple monitors, or plug single monitor into other video card connector on multi-monitor cards.
  • Update (or roll back) video card drivers.
  • Install USB Cumulative update in KB941600.
  • Blame a virus or adware/spyware.
  • Boot from Vista DVD and use Repair function.
  • Use System Restore to return to “Last Known Good Configuration.”
  • Reinstall Vista.
  • Reformat the hard drive.

Each “solution” works for some people and not others. I ran across at least one person complaining that their screen was still black after reformatting their hard drive and another continued to have a black screen after replacing his video card.

Of course, this is undoubtedly not a single problem but rather similar symptoms resulting from a lot of different problems.

I used my notebook computer to connect to my office computer using Remote Desktop. My desktop appeared and it was clear that the office computer was starting up completely normally in all respects except sending a signal to the monitor. I tried to change the display resolution and refresh rate, which turns out to be hard to do when the monitor is black. Those settings aren’t available in Remote Desktop sessions and there’s no obvious command line options.

After three or four hours I had a black screen and a headache, along with a lingering suspicion that it might be a hardware problem with the video card after all. I shut the computer down overnight. This morning when I logged in, my desktop appeared in all its bright glory – no black screen – and everything has been working for five hours straight. Could the video card be overheating? The system was set to put the monitor to sleep – did I overlook that and it won’t happen again until the monitor goes to sleep next time?

I’ve got a new video card on the way. I wonder if it will make any difference?

When I’m cautious with my clients about troubleshooting hardware problems, it’s experiences like this that are in my mind. But next time you want to throw a computer through a window, call me so I can help.

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