Microsoft says that a problem with its Windows operating system, dubbed¹ the 'Black Screen of Death' is not due to its latest security update.

微软称，Windows操作系统出现的“黑屏假死”现象不是由于其最近的安全更新引起的。

Windows 7 was released in October

Some Windows users are confronted by a totally black screen after they log on to their system.

It was thought that a security update on 10 November had been the cause, although this has now been discounted.

Reports suggest the problem also affects Windows Vista² and XP, which experts are putting down to（归因于） malware（恶意软件）.

In a blog posting on its security site, Microsoft said that it had investigated the claims and "found that our November Security Updates are not making changes to the system that these reports say are responsible for these issues".

The firm said that the behaviour was associated with malware, such as Daonol, and that this was probably the root cause.

Software firm Prevx, who had said the November update may have been to blame, have since retracted³（缩回，收回） their statement, saying it had been a "challenging issue" to identify the cause.

"Having narrowed down a specific trigger for this condition we've done quite a bit of testing and re-testing on the recent Windows patches（碎片，补丁） including KB976098 and KB915597 as referred to in our previous blog," the firm wrote on its website.

"Since more specifically narrowing down the cause we have been able to exonerate⁴（免除责任，确认无罪） these patches from being a contributory factor."

Prevx apologised to Microsoft for "for any inconvenience" its earlier claims may have caused.

The firm has issued a fix for the problem, which is says could affect "millions" of computers.

"Users have resorted to reloading Windows as a last ditch（最后防线） effort to fix the problem," the firm's David Kennerley wrote in a blog post.

"We hope we can help a good many of you avoid the need to reload."

Unknown problem

The firm said its fix did not work in all cases.

"There can be many causes," said Mr Kennerley.

"But if your black screen woes⁵ began in the last two weeks... or after running any security program (including Prevx) to remove malware during this time, then this fix will have a high probability of working."

Mr Kennerly said the firm had identified "at least 10 different scenarios⁶ which will trigger the same black screen conditions".

"These appear to have been around for years now," he said.

The firm reports that the problem affects editions of Windows 7, Vista, XP, NT, and Windows 2000.

Microsoft said that people who are affected⁷ by the problem should contact its customer service line.

The "black screen of death" moniker（名字，绰号） is a play on the "blue screen of death", which appears when Microsoft operating systems crash（系统崩溃）.