Are you aware that there is a dangerous bug in all versions of Windows XP and Windows Server 2003 that puts computer users at risk? Hackers could exploit a vulnerability using Internet Explorer 7, and possibly other programs, and take over a user’s computer for a variety of nefarious purposes, such as stealing passwords or pumping out spam. Well, Microsoft Corp. issued two serious security fixes in a regular monthly update Tuesday as its most urgent “critical” rating. The other fix, which Microsoft gave the second-highest “important” rating, is for computers running versions of Windows 2000 Server and Windows Server 2003. Hackers could exploit the flaw in Microsoft’s program to redirect Internet traffic from legitimate sites to fake ones.