Microsoft Update offered me two suppsedly important updates for Office 2010 on Windows XP a couple of days ago, KB2863821 and KB4461522.
They installed fine, but the next day I came to use Word, and it would not run, with the error message -
Application popup: winword.exe - Entry Point Not Found : The procedure entry point GetDateFormatEx could not be located in the dynamic link library KERNEL32.dll.
This was followed by "The operating system is not presently configured to run this application".
I quickly found that no Office programs would now run, with the same error messages.
I removed the two updates, and all returned to normal.
I have no idea which of the updates caused the problem, and I haven't been offered either of them again so far, but if you are offered them, beware as they may well completely break your Office installation!