I've tried all the fixes available to install KB2686509 w/o any results. Now I found this in the log...
11.587: 2012/08/25 10:52:21.696 (local)
11.587: C:\WINDOWS\SoftwareDistribution\Download\3438087687b5dd8accc81e44f72f02e7\update\update.exe (version 6.3.13.0)
11.607: DoInstallation: GetProcAddress(InitializeCustomizationDLL) Returned: 0x7f
11.607: Failed To Enable SE_SHUTDOWN_PRIVILEGE
11.617: Hotfix started with following command line: -q -z -er /ParentInfo:aff11faffeb9774fb48bf16e403d71ec
11.667: In Function GetReleaseSet, line 1240, RegQueryValueEx failed with error 0x2
13.089: Return Value From IsMachineSafe = 0
13.089: IsMachineSafe returned 441092
13.089: Fist Condition in Prereq.IsMachineSafe.Section Failed
13.089: Condition Check for Line 1 of PreRequisite returned FALSE
13.119: ReadStringFromInf: UpdSpGetLineText failed: 0xe0000102
13.119: KB2686509 Setup encountered an error: Setup cannot continue because one or more prerequisites required to install KB2686509 failed. For More details check the Log File c:\windows\KB2686509.log
13.139: ReadStringFromInf: UpdSpGetLineText failed: 0xe0000102
13.139: Setup cannot continue because one or more prerequisites required to install KB2686509 failed. For More details check the Log File c:\windows\KB2686509.log
13.139: Update.exe extended error code = 0xf0f4
Any suggestions?