The computer being powered off before it was finished writing the files would probably explain the 0 size. The 0-size files may not even be the actual data. Often, live data collection goes to a temporary file until it is closed "gracefully". The "lock" you see would not be unusual for files being actively written to. It is to prevent the files from being used or corrupted while they are "open".
Windows update can slow the computer while it's running (competing for resources), and it can interact with Windows files, but I've never heard of it affecting files that have nothing to do with Windows (or Windows-related, like drivers). Normally, you can continue to work while Update is running. Typically, if Update does not complete...