Get installed hotfixes

1. Here is a command: wmic qfe list full
2. On XP, go to the registry directly: 
   Instances of this class represent updates found in two places in the registry:

   • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\    CurrentVersion\Hotfix

   • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates

3. On Vista, the registry doesn't exist any more. Try the WMI Class: Win32_QuickFixEngineering Class http://msdn.microsoft.com/en-us/library/aa394391(VS.85).aspx