Fingers crossed, this problem seems to have gone away for us. None of our student machines have this error in the event log after 1st Feb.
We were having the problem on Windows 8.1 pcs, with Office 2013.
I am wondering if this January Office update fixed it: https://support.microsoft.com/en-us/kb/3114486
"After you install the November 10, 2015 update for Office 2013 (KB3101360) or the December 8, 2015 update for Office 2013 (KB3114333), Office applications may hang or crash. This can affect one or more Office applications, such as Outlook 2013, Word 2013, Excel 2013, OneNote 2013, and PowerPoint 2013."
Our ntdll.dll version is 6.3.9600.18202. It has a modified date of 19/01/2016 so this might also be what fixed it for us. I don't think that was included in the above Office update - possibly in a Feb 9th windows security update.
