Thanks, guys.

I tried to fit all the info I had into that post, but I forgot one thing. I made sure to take a peek at the details of the update, and it appeared that only one thing was being changed, and I thought it only had something to do with IE. I have no idea what that could have to do with anything to make this happen, but I agree with all your theories.

Oh, and to answer one person's question: no, Update only asked to be rebooted once, and I said no because I wanted to close down the programs I had running. Immediately after that, however, I shut off my computer.