I have the same black screen now, but I know WHEN it started if not WHY. I have a brand new Lenovo Thinkpad R61 with Vista Business on it. One of the things it came with was a trial version of Office 2007. The computer has worked normally for a couple of weeks, then when I uninstalled all the Microsoft Office trialware and rebooted - bang! Black Screen of Doom.

In my case the screen comes up black with the Documents folder open. I can hit Ctl-Alt-Del, bring up Task Manager, kill process explorer.exe, then restart it through the applications tab, and the desktop comes back.

I have noticed the following:
1. The computer logs in with the default user, no login screen is presented.

2. The hard drive runs constantly until I do the work-around and the desktop comes up.

3. Turning off UAC did not help this problem, but sure cleared up a LOT of annoyances.

Since explorer.exe WILL start after doing the workaround, I am thinking this is either a problem with the boot sequence (a bad driver), or the login sequence. Right now it would appear that something is not loading in the boot-up that explorer.exe requires, but DOES load after the fact.

I am now thinking there might be a registry entry somewhere that is causing this behaviour, but nothing yet looks out of place.

Any thoughts?