OK, what the tarnation is a Microsoft Critical Update Notification?

a. a crafty way to spead a virus

b. a clever Microsoft sales pitch

c. an honest to goodness free update that won't clog up your computer, won't add your name to a sucker list, and won't spread your email address all over the WWW, but will improve the operation of your computer

Frankly, I don't have any idea, but after that 19-day, $100 experience with "Stratavirus" I tend to be cautious. In this day of crafty internet pirates, you can't even trust a trusted logo anymore. (I found that out with my website host.) I wonder if this "notification" really came from Mircosoft, so naturally, I don't intend to click on "Notify Me Later" which supposedly starts a 24 countdown, or "View Critical Updates" or even the X in the upper right corner. Any of these actions may be all it takes to log jam my computer all over again.

Can anybody help me on this, or should I just write "Dear Abby?"
Howard