Didn't work for me, either. Can't find a manual download to try, either. MS Download Center doesn't recognize "2686509".
According to KB 2686509, if the user cannot find "Faultykeyboard.log" in his %windir% folder (*which I cannot*), he is to contact MS Support. Every possible support path leads back to MS Answers. You are the only hope.
[KB2686509.log]
1.750: ================================================================================
1.750: 2012/05/09 03:16:09.531 (local)
1.750: C:\WINDOWS\SoftwareDistribution\Download\3438087687b5dd8accc81e44f72f02e7\update\update.exe (version 6.3.13.0)
1.781: DoInstallation: GetProcAddress(InitializeCustomizationDLL) Returned: 0x7f
1.781: Failed To Enable SE_SHUTDOWN_PRIVILEGE
1.781: Hotfix started with following command line: -q -z -er /ParentInfo:9c5f84a85a4fab48a313c7efa718d6ad
1.781: In Function GetReleaseSet, line 1240, RegQueryValueEx failed with error 0x2
3.422: Return Value From IsMachineSafe = 0
3.422: IsMachineSafe returned 441092
3.422: Fist Condition in Prereq.IsMachineSafe.Section Failed
3.422: Condition Check for Line 1 of PreRequisite returned FALSE
3.438: ReadStringFromInf: UpdSpGetLineText failed: 0xe0000102
3.438: 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
3.453: ReadStringFromInf: UpdSpGetLineText failed: 0xe0000102
3.453: Setup cannot continue because one or more prerequisites required to install KB2686509 failed. For More details check the Log File c:\windows\KB2686509.log
3.453: Update.exe extended error code = 0xf0f4
23.797: ================================================================================
23.813: 2012/05/09 07:16:31.109 (local)
23.813: C:\WINDOWS\SoftwareDistribution\Download\3438087687b5dd8accc81e44f72f02e7\update\update.exe (version 6.3.13.0)
24.078: DoInstallation: GetProcAddress(InitializeCustomizationDLL) Returned: 0x7f
24.078: Failed To Enable SE_SHUTDOWN_PRIVILEGE
24.110: Hotfix started with following command line: -q -z -er /ParentInfo:b02ccbfad7ec4749b6f0d960f7fccebd
24.110: In Function GetReleaseSet, line 1240, RegQueryValueEx failed with error 0x2
26.156: Return Value From IsMachineSafe = 0
26.156: IsMachineSafe returned 441092
26.156: Fist Condition in Prereq.IsMachineSafe.Section Failed
26.156: Condition Check for Line 1 of PreRequisite returned FALSE
26.188: ReadStringFromInf: UpdSpGetLineText failed: 0xe0000102
26.188: 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
26.188: ReadStringFromInf: UpdSpGetLineText failed: 0xe0000102
26.188: Setup cannot continue because one or more prerequisites required to install KB2686509 failed. For More details check the Log File c:\windows\KB2686509.log
26.188: Update.exe extended error code = 0xf0f4
1.734: ================================================================================
2.015: 2012/05/09 07:19:15.296 (local)
2.296: C:\WINDOWS\SoftwareDistribution\Download\3438087687b5dd8accc81e44f72f02e7\update\update.exe (version 6.3.13.0)
2.500: DoInstallation: GetProcAddress(InitializeCustomizationDLL) Returned: 0x7f
3.515: Failed To Enable SE_SHUTDOWN_PRIVILEGE
3.515: Hotfix started with following command line: -q -z -er /ParentInfo:c1776a81a2fb4d4e99767689d7b2823e
3.562: In Function GetReleaseSet, line 1240, RegQueryValueEx failed with error 0x2
3.718: Return Value From IsMachineSafe = 0
3.718: IsMachineSafe returned 441092
3.718: Fist Condition in Prereq.IsMachineSafe.Section Failed
3.718: Condition Check for Line 1 of PreRequisite returned FALSE
3.734: ReadStringFromInf: UpdSpGetLineText failed: 0xe0000102
3.843: 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
3.953: ReadStringFromInf: UpdSpGetLineText failed: 0xe0000102
4.015: Setup cannot continue because one or more prerequisites required to install KB2686509 failed. For More details check the Log File c:\windows\KB2686509.log
4.015: Update.exe extended error code = 0xf0f4