On boot, when I hit the F12 key to bring up the boot menu, the screen displays the various kernels and other boot options. In the text below this menu it says I can hit 'p' to bring up a menu with other options. I've done this with the last two boot-ups and no other menu or options appear. Is something missing? (I also tried Alt-p, Shift-p, Ctrl-p and a few other keys and there's no change onscreen.) I'd like to know also how to select single user mode, but haven't found a way to do that. Thanks much.