What Service Pack is installed? Should be Service Pack 2. You can check by right clicking on My Computer and selecting Properties. If you don't have SP2 then you can download and install it from links below.
Note: If you don't have SP1 then you need to do that first.
Did the screenshot in your original post appear after you attempted to reset your Windows Update components? That will clear the list of updates installed by Windows Update at Windows Update | View Update History (i.e., Most recent check for updates: Never / Updates were installed: Never) but you should still be able to view your installed updates at Control Panel | Programs | Programs and Features | View Installed Updates.
If you click the Check for Updates button in your Windows Update interface and the initial "Checking for updates…" phase appears to run for several hours (or even days) without throwing an error message, please note that most Vista SP2 users are currently having the same problem. See the step-by-step instructions on page 1 of m#l's thread Updates not working, it has been searching for updates for hours in the MS Answers forum for a possible workaround.
