Sep 2, 9:39 PM (ET)

By ALLISON LINN

SEATTLE (AP) - Though Microsoft Corp.'s new security update package is all about protecting systems from worms, viruses and spyware, it can't do much about what's already on computers - and that could pose a problem.

The company is warning users of the Windows XP operating system to check for spyware before downloading the free massive security update, called Service Pack 2.

Barry Goff, a group product manager at Microsoft, said some spyware could cause computers to freeze up upon installation of the update.

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