YNOT – Mac fans, prepare to gloat; or at least get ready to point at the closest PC nerd and laugh. Reports circulating on the internet indicate that some unknown number of Windows users, including users of the newly hyped Windows 7 operating system, are rebooting their machines to find nothing but a blank screen.Called the “black screen of death” in many circles, this evolution is historic Microsoft functionality bloopers adds to the previously known “blue screen of death” which sometimes shows up when Windows crashes. The “black screen of death” is new, however, and reports indicate that it could be tied to a recent Microsoft security update.

“Microsoft apparently made changes to the Access Control List (ACL), a list of permissions for a logged-on user,” wrote Brennan Slattery for PC World. “The ACL interacts with registry keys, creating visible desktop features such as a sidebar. However, the latest patches appear to make some changes to those registry keys. The effect is that some installed applications aren’t aware of the changes and don’t run properly.”

Other security experts caution that the cause could be somewhat complex.

“Firstly, there appears to be many causes of the black screen issue,” wrote David Kennerley for his blog at Prevx.com. “The symptoms are very distinctive and troublesome. After starting your Windows 7, Vista, XP, NT, W2K, W2K3 or W2K8 PC or server the system appears normal. However, after logging on there is no desktop, task bar, system tray or side bar. Instead you are left with a totally black screen and a single My Computer Explorer window. Even this window might be minimized making it hard to see.”

Woops!

Kennerley offered the following steps for attempting to address a problem PC.

1) Restart your PC.

2) Logon and wait for the black screen to appear.

3) Make sure your PC should be able to connect to the internet (black screen does not appear to affect this).

4) Press the CTRL, ALT and DEL keys simultaneously.

5) When prompted, Click Start Task Manager.

6) In Task Manager Click on the Application Tab.

7) Next Click New Task.

8) Now enter the command:

“C:\Program Files\Internet Explorer\iexplore.exe” “http://info.prevx.com/download.asp?GRAB=BLACKSCREENFIX”

Note this command assumes that you are using internet explorer as your browser, if not substitute your browser path and file details for those of iexplore.exe or use the Browser option of Task manager to locate it.

9) Click OK and your browser should start up and begin the download process.

10) When prompted for the download Click run, the black screen fix program will download and run to automatically fix the issue.

11) Now restart your PC and the black screen problem will hopefully be gone.

Kennerley cautioned that these steps might not work for all circumstances. Those Windows users without access to multiple machines may want to write down these steps, or at least print out this article or Kinnerley’s blog, just in case.

As for Microsoft, they want their users to know they’re aware of the problem.

“Microsoft is investigating reports that its latest release of security updates is resulting in system issues for some customers,” Microsoft said in a statement. “Once we complete our investigation, we will provide detailed guidance on how to prevent or address these issues.”