After a reboot, Windows Explorer began to crash and restart constantly with an Event ID 1000 error. Windows Help was useless, so I opened Event Viewer and saw the following:
It's curious that a file which is part of the third-party Windows 7 Codec pack seems to be responsible:
Faulting module path: C:\Program Files\Win7codecs\filters\DivXMFSource.DLL
Fortunately, I got around this issue by simply uninstalling the codec pack as described here, by executing the file Win7codecs.msi in a subfolder contained immediately under C:\ProgramData\Win7codecs\, and then choosing Remove (the only option available via Control Panel \ Programs \ Programs and Features is to perform a "Repair", which didn't help in my case).