Ever struggled with a software bug that you suspected was caused by a Windows Update? I know I have. That sinking feeling that a bug suddenly appearing out of nowhere along with the faint memory that Windows asked you to install a number of updates yesterday (or late last night in the software development business). Putting those two and two together makes you feel really "special". Either that or it makes you feel like a real software developer who uses deductive reasoning to find the real problem.
Either way, you really need the list of installed Windows updates to research. Windows Vista has made this really easy (see Control Panel, Windows Update, View update history). Thank you, Microsoft. Previous versions of Windows involve DOS commands or other minutiae. I would recommend a quick download of WinUpdatesList from NirSoft. This is the quickest and easiest way to get a list of recently installed Windows Updates.