Uninstall Latest Windows Update Without Logging In

After turning on my computer today, I noticed that the "shut down" icon in start menu had the familiar triangle referring to updates. I closed things down and selected it to "Shutdown and install updates". I keep my Windows as up to date as i can, so this was a recent update.

The problem is that upon starting the computer, I could get to the log in screen with both the Administrator and user accounts visible, but when attempting to select either one to log in, the screen flickers black once for a half-second, then kicks me back to the user select screen. How can i undo this last update without logging in? I tried inserting the windows disk to use the system restore feature, but it claims that "No restore points have been created on your computer's system drive" yet as far as I've seen, each update has been initiated with a "creating system restore point" loading bar, so how can this be? I've attempted logging in in safe mode as well. The same black screen, it just took longer before I got kicked back.

Or additional information I can provide?

Edit - If possible, does anyone know of a program or command that can bypass the log in screen and immediately log in? Maybe if I could do that and get into the system itself, I could undo the upgrade on my user account.