Microsoft is warning Windows users of a security flaw relating to animated cursor (.ani) files, which could allow an attacker to take over a user's PC.

Users are being warned about web sites and e-mail attachments containing malicious code that takes advantage of the vulnerability.

Once the code is executed it could allow an attacker to take control of the user's PC.

Microsoft says users of Outlook 2007 are protected but Outlook Express users are vulnerable to e-mail attachments that contain the code.

Microsoft is planning to issue a security update for Windows to patch the flaw, and has also updated its Windows Live OneCare security software to protect against the vulnerability.

Users of other security software are urged to make sure their programs are up to date.

Meanwhile, security experts warn about a fake email that appears to be an invitation from Microsoft to download beta 2 of Internet Explorer 7, but the download actually contains a worm virus.

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