Keep your windows up to date or risk infection.  This critical bug could allow a hacker to gain control of your system.  The bug effects all version of Windows from XP on including the beta for Windows 8 as yet unreleased. See the article here: Critical Windows bug could make worm meat of millions of high-value machines. Here is the Bug report and Microsoft’s Solution: CVE-2012-0002: A Closer Look at MS12-020’s Critical Issue.