More bad news for Microsoft's delayed operating system Vista - the European Commission is widening an investigation into whether or not it breaches competition law.

Microsoft and the Commission were already discussing the oft-delayed software.

Today also saw full-page adverts in the Financial Times from security vendor McAfee. The open letter, addressed to "Dear computer users around the world,", warns that Vista is likely to make security problems worse.

The letter says that the best defenders of Microsoft's operating systems have been third party developers and security firms. But for the first time with Vista Microsoft is stopping security companies accessing the "kernel" - the heart of its operating system.

The letter says: "For starters, customers should recognise that Microsoft is being completely unrealistic if, by locking security companies out of the kernel, it thinks hackers won't crack Vista's kernel. In fact, they already have...

"Microsoft's new approach is misguided in principle, bad for innovation and competion. Above all it is bad for users."

McAfee asks Microsoft to return to its previous collaborative approach.®

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