Thanks for the idea - no I hadn't - because they still showed up in the GAC when I checked, so I assumed they were fine. Sorry for the delay in responding, but I was on plan G: reinstall VS. Brute force and ignorance, yes, but it worked (in the sense that the problem has gone away). It'll probably still keep me awake wondering what the heck caused it though... :laugh:
Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.