A "worm" spread across the Internet on Monday, causing computers to restart as it targeted

Microsoft

(MSFT) - Get Report

, according to published reports.

The U.S. government has warned against the viruslike worm, which accesses vulnerable computers through a flaw in Microsoft Windows software.

Researchers discovered it about 3 p.m. EDT, and reported thousands of infected computers inside universities, businesses and homes,

The Associated Press

reported.

Infected computers were programmed to launch an attack on a Web site operated by Microsoft on Saturday. The site, windowsupdate.com, is used to download repairing software patches to Microsoft customers to prevent such infections,

AP

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reported.

Last month, Microsoft

posted a security warning about the worm on its main Web site.

The infection was named "LovSan" because of a note left behind on computers: "I just want to say LOVE YOU SAN!" Researchers also found another message apparently aimed at Chairman Bill Gates: "billy gates why do you make this possible? Stop making money and fix your software!"

AP

reported.

The outbreak has been expected since July 16, when Microsoft acknowledged the flaw affected nearly all versions of its Windows operating system software.

The flaw affects technology used to share data files across networks, involving "buffer overflows" that can trick software into accepting dangerous commands,

AP

reported.