Cannot install IE10 from Windows Update, Error 9C57

When I attempted to install IE10 from Windows Update, the update failed with Error 9C57. There was also a prior failure (also this morning) to install an optional update, Platform Update for Windows 7 x64 edition (KB2670838). Finally, while this may be entirely unrelated, I noticed earlier this week that the "Turn Window Features On and Off" function under Programs and Features of the...