windows updates

My computer is windows 7 home premium 64bit.I have windows updates turned off,I manually install security only updates.Last night I rebooted computer and windows installed and configured a update.I can not find the update in view update history or event logs.As I said I have windows set to not update.Is that normal for microsoft to install a update like that.This is a clean install,fully updated,but not with optional updates,just security only updates.Any help would be appreciated.

On occasion, it seems that sometimes Microsoft does this sort of thing. I'm not sure what you can do about it, except stay on top of things as best you can.

Thanks for reply.I do try to stay on top of all things regarding updates to computer.I'm sure as I can be that computer is clean,because as I said it's a clean install.I would hope they-microsoft- would let someone know they were going to update computer and not do it secretly.