As a simple FYI to those who aren't yet privy to this fun tidbit, I'm going to paste-in a reply I just typed in response to another poster.
In short, this is how to clear (safely) your Windows/MicrosoftUpdate cache (or, simply-put, a history of logged updates, which suggests progression and no need for prior updates.)
Let it be said that even though Vista is a secure, great OS overall, sometimes one needs to be sure they've got all their "hotfixes," etc. Here is my method, which I verified with MS Tech Support as a valid/safe one. I hope someone out there benefits from this as I have:
if you're having problems with Windows/MicrosoftUpdate, it's a good (and safe) idea to clear your Update Cache. This does NOT delete hotfixes. It simply saves disk space and allows Windows to do a fresh scan for missing or overlooked updates. Vista is a great OS, but it's imperfect. Here are the steps:
1.) Go to Start / Accessories / Command Prompt (CMD)
2.) Right-click on the icon for CMD and choose RUN AS ADMINISTRATOR.
3.) Now, we'll shut down the 3 locking handle-type services tied-into WindowsUpdate so you can manipulate the folder. However, you'll definitely want to be ready. Open Windows Explorer and navigate to: C:\Windows\SoftwareDistribution. DO NOT OPEN THE FOLDER. Just keep this handy.
4.) In your "elevated" Command Prompt (run as administrator,) type each of the following verbatim with no quotes:
a.) net stop wuauserv (wait for response)
b.) net stop crytpsvc
c.) net stop bits
5.) IMMEDIATELY navigate back to your SoftwareDistribution folder. Highlight each and every single folder in it. Delete them all. Go back to your CMD prompt.
6.) In CMD, type:
net start wuauserv
net start cryptsvc
net start bits]
7.) Lastly, check for new updates. Since the system will THINK it hasn't been updated, it will be one longgggg cycle. Opt-in for Microsoft Update if you have Office2003/2007. In any sense, the one super-lengthy check is a 1-time thing. That's the best way to recover from the Vista-famous 80070002 error & also missing updates.
I hope this helps!