Microsoft has released a command-line tool that easily enumerates all of the installed fixes by Microsoft Knowledge Base article number. Customers can then confirm that they have installed the appropriate set of fixes before using a valuable support incident and potentially experiencing unplanned down time.

Windows XP (64 bit) Patch: Qfecheck.exe Verifies the Installation of Windows XP Hotfixes

Windows XP (32 bit) Patch: Qfecheck.exe Verifies the Installation of Windows XP Hotfixes