Microsoft today pushed out software updates to fix a large number of security flaws in computers running its Windows operating systems and other software. Notable among the patches is a critical roll-up of fixes for Internet Explorer, the Web browser used by the majority of the world’s online population. Today’s bundle of fixes corrects at least 17 security vulnerabilities found in Microsoft products ranging from Windows to Microsoft Office and Works, to Internet Information Services (ISS), a popular Web server. At least 10 of the flaws earned Microsoft’s most serious “critical” rating, meaning they could be exploited by attackers to break into PCs and install software with little or no help from the victim. For example, the IE update addressed four of those critical flaws, each of which Microsoft said could be exploited merely by convincing an IE user to visit a malicious/hacked Web site or open a poisoned HTML