The other day, Kitty Kilobyte called up Power Downloader with a pressing concern. Was there an easy way to tell if Microsoft had pushed Windows XP Service Pack 3 to her computer yet?

WinUpdatesList shows you all Windows updates and provides in-depth information to boot. (Credit: NirSoft)

Some of you may laugh at Kitty, but besides displaying terrible social skills, Microsoft updates are no joking matter. Sure, Power knows that they may not always be released as planned, like with XP SP3 or Vista SP1 earlier this week, but when they do get downloaded to your machine they're important. Patching security holes and performance enhancements can make the difference between running a healthy computer and running one that's just moments away from the grave if a nasty piece of malware gets in.

Once he explained what happened to SP3 this week, Power introduced Kitty to a program that shows you instantly just which Windows updates are installed on your computer. Called WinUpdatesList, it does more than merely show you what the updates are. Click on an update in the top pane, and the list of files it installed appears in the bottom pane. Next to each file name, you get its full path location, version, checksum, and a brief description.

The upper pane shows a similar level of detail on the update, offering up help links, installation date, update type, uninstaller location, and more. Toolbar buttons provide one-click access to Web help, a status report in HTML, and copying the information to your clipboard. Unfortunately, it only works on Windows XP right now--not Vista.

Power Downloader recommends you keep WinUpdatesList in your toolbox so you'll never again have to worry about what your Microsoft updates are doing to your computer.