I was using mt computer 2 days a go when a message came through to say I had to update my windows, I did as indicated and my computer was locked, as I'm no novis I spent several hours tracking the the trojan down & removeing of code that had been inserted in the windows security. Be on your guard of what are windows updates.
Nothing new, these scams are the number one infection point for any system. If in doubt use the system provided tools in this case Control Panel - Windows Update in doubt or in the case of Flash/Java/PDF go to Adobe/Sun as these are often spoofed as well.
MS rarely does an out-of-band patch, they generally patch Windows on the second Tuesday of each month. If there is an OOB patch they'll will announce it to the tech media so people are prepared.
You was lucky in this instance as there is increasing amounts of RansomWare that will encrypt your drive so you are forced to pay a ransom or restore from a back up and there is no protection against these except having offline back ups and using common sense.