Ok everyone, thanks for the tips. I was able to get the GRUB menu by pressing Shift on startup, and then I booted into the second newest kernel shown, which worked. I went into a terminal prompt and tried the sudo apt-get upgrade command, but when I restarted Ubuntu it went back to the keyboard not working. There must be a bad driver or something in the newest kernel. Is there a way I can delete that newest kernel? Otherwise I suppose I could modify GRUB so it prompts me at startup to choose which one to boot.