Sometimes when I close Word documents winword.exe still runs in background (but there's no document open) and when I then want to open a word file nothing happens. I first have to open Task Manager, stop the winword.exe process and then I can open another document.
I'm working on Windows 7 Professional 64 bit (Service Pack 1) with Office Word 2010 Home & Student.
Until now I couldn't figure out any pattern after which actions it happens. I already reinstalled Word with no difference. The Office Suite is up to date.