Yesterday, while I was trying to install an old driver for my printer/scanner from the manufacturer's DVD-rom, the screen blacked out, leaving only the mouse pointer was visible. Gradually the task bar appeared, and I could reboot the machine as usual.

In the meantime, though, several of my hard drives had new names/letters (hard drive 'I' became 'J', and 'J' was renamed 'L').

Also, the media network sharing options I'd organized were suddenly reversed, and will have to be redone.

I'm not expecting an explanation, and I know I can change them back. It's just a bit peculiar.

If anybody's interested, here's the event log (I think it's the right one):

The application-specific permission settings do not grant Local Activation permission for the COM Server application with CLSID
to the user NT AUTHORITY\SYSTEM SID (S-1-5-18) from address LocalHost (Using LRPC) running in the application container Unavailable SID (Unavailable). This security permission can be modified using the Component Services administrative tool.