Problem with single-user mode in Mac OS.
It is difficult to give a precise solution to this problem without your MacBook. However, I can give you some advice.
Try again to enter the single-user mode.
0. Check if Open Firmware Password Protection is disabled.
1. Shut down your Mac.
2. Press the power button.
3. Immediately press and hold the Command (Apple) key and the "s" key for the single-user mode. (Command-S)
You will be able to enter successfully the single-user mode after you'll see the white text.
Problems with the keyboard.
In some models of MacBook the keyboard is not recognized before booting the system, especially aluminum.
1. Connect another keyboard and your Apple's laptop and try to use the single-user mode with it.
2. If you have no other Apple keyboard or cannot connect it, try to use a regular PC keyboard.
If these tips are not useful to you, I advise you to contact the Apple Tech Support.
Not helpful? Ask our experts. It's fast and free.