On a Win7 system, I made a very basic study in MediaLab v2012 that opened 3 Word 2007 files (*.doc).
Without Word already running, I went through the study, Word text displayed properly.
However, when the study finished and I closed MediaLab, Word had remained open, minimised in the task bar with no document shown, only the empty Word frame.
I tried .docx and .rtf files; both invoked winword.exe, and left Word open after MediaLab was finished and closed.
I also ran the same experiment using PowerPoint Show .pps files. When MediaLab was finished, PowerPoint was closed.
Compared to the two posts about Word 2010, using Word 2007 produced no error messages; however, MediaLab leaves Word open when such files are used.
A short-term solution is to not rely on Word, replace each .doc file with the identical content save as .htm/.html.