Microsoft critical updates are usually just that--critical. It's important to install the "urgent" or "critical" ones. You can pick and choose among the "optional" ones.

If you have XP or Vista, call up your Control Panel and look for an icon labeled "Security Center," and work from there. There will be something there called "check for latest updates." Use it.

There will also be an "automatic updates" section, and near the bottom, a "manage settings" button for automatic updates.

I have mine set to check automatically, but not do anything until it asks me ("notify me but don't automatically download...") When something critical is available (Microsoft usually issues major updates on the second Tuesday of the month), the computer has a little icon that shows up at the bottom of the screen while I work to indicate that there are critical updates available.

Some people have this set to automatically download and install. I prefer to keep more control over the process.

It sounds like you might have this set to "download updates for me, but let me choose when to install them." I suspect the computer has updates in the hopper that it would like to install. Do it.

I recommend making sure you're up to date on the fixes. It is important.