Vista: never-ending updates, can't log in

When I was at work, my vista ultimate must have restarted. Now I can't get
past the log-in screen. Every time I try to log in by clicking my name, I
get the "Welcome" and then "Logging off".

Then I noticed that there was an option to install updates. Tried that.
Installed 5 updates. When I restarted, after configuring updates, I got back
to the signin screen. Click my name, "Welcome" then back to "Logging off".
Then I noticed AGAIN that there are updates. This time, it installed 3
updates. After all that, same "Welcome" "Logging off" sequence. AGAIN
updates. 4 this time. Same results. Then 3. Same results. Then 5. Just
tried again. 5 more updates to install. And not once have I been able to
log in!

What the heck is going on? Anyone have any ideas? HELP!