Macbook Startup Problem

I`ve just done a software update on my friends MacBook and although the download went fine after the system rebooted it seems stuck at a black screen. I have tried pressing keys and various other things but nothing seems to happen. When I press the keys I get the beep noise like when something has gone wrong.

Any ideas as to what this could be and how to cure it? I`m running from the mains so the battery isn`t flat. I`m new to this Mac stuff so I haven`t a clue.

Thanks for any help,
Jason.

OK the screen brightness setting had just gone all the way down for some strange reason, all is OK now.

Jason.

I've seen that happen before.

Scary, wasn't it? :-)

Yes :)

Jason.