Microsoft says it's investigating reports that its latest release of security updates are causing some Windows (7, Vista and XP) machines to freeze after starting, and display a black screen with a single My Computer Explorer window.

"Once we complete our investigation, we will provide detailed guidance on how to prevent or address these issues."

Security software maker, Prevx, first reported the problem surrounding the November 10 update, and has created a tool to fix the issue if you're affected: [Prevx via PC World and TechFlash]