Black screen

Tonight when I returned from the swimming pool I turned on my laptop (my home laptop not the work one). And nothing happened. I mean I was facing a black screen, only the power and some other buttons were blue, but that's it :( Before panicking I thought maybe the battery is empty so I plugged the laptop. Tried again, nothing.
I forced the system to stop and restart, nothing.
Now I'm a bit worried. I go take the shower thinking maybe the computer needs some rest. Did not change much.
So here I am facing a black screen, already thinking that my laptop was dead and I had lost all the data. Sad, upset but strangely calm. I switched on the work laptop and searched on google for a solution (basically that was my last hope).
And I found plenty of entries related to similar problem. Some HP Pavilion dv20xx and other series have even had an extension of warranty. Of course not mine :)
After 1 hour spent browsing different forum, with solution ranging from "call HP and send computer back" to "it's over. your computer is dead" I found the following:
-----------
This just happened to me today, exactly one year after I first got the computer. The power was on but the screen was blank. It was like there was nothing working in there at all.
BUT I know how to fix it, and it's working great now.
What you do is take out the battery, then disconnect all power to the computer so it's not able to retrieve power from anywhere.
Then you press the ON button and hold it for exactly 30 seconds. (can't be less or it won't work)
Then you get the AC power cord and plug it in, and turn on the power supply so the light glows. (the battery MUST still be out)
Then you switch on the computer and it should work.
After that you just shut down the computer and put the battery in again and switch it back.
What this does is reset the components of the computer, I don't know why it has done this but this method fixes it. I'm real glad it's ok cos I might've had to reformat (which I didn't really want to do cos I had 150 GB worth of files on there...)
---------------
I was skeptical (especially about the 30s part) but desperate so I tried. And it worked!
Everything is back to normal. Still tomorrow I'll bring my external drive home and will back up everything. It's been a bit more than 1 month since my last back up and so many pictures I don't want to lose.
Keep your fingers crossed it won't happen again.