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It was more than likely Java (Sun Microsystems) that asked to run the update. This is usually a little icon that is an orange and white cup of coffee in the bottom right corner by the clock that will pop up with a small window and ask if you want to download the update. It is different than the yellow ! icon that Microsoft uses for their updates. I would say that it is probably a good idea to download and then install the Java update; it more than likely fixes security vulnerabilities. Once updated, you can go to Control Panel and click the Java icon. It may take up to a minute for the window to open, for some reason. From there, you can click the update tab and choose to never check for updates.
Although updates got a bad rep a couple years ago, they are typically much more reliable these days and very necessary in the cat-and-mouse game constantly being played with hackers and virus writers.