Macbook won't shut down

Hey guys,
i just got a new 13" 2.4Ghz Aluminum Macbook last tuesday. I was a PC user before that.
The laptop is glorious, except in the part that it won't shut down properly!!
I click the "shut down" under the apple, but most of the time when I close the lid the white is still on and the computer is still running. I go ahead and try to switch it back on, but it does not.
-- I m obliged then to press the shut down button on the keyboard for 5 secs to shut it down completely.

Does this sound really bad? should get back to the apple store or what?

When you click shutdown under the apple - a window will pop up that gives you like a minute or 2 before it actually shuts down - do you click the shutdown button there and wait for the screen to go black and the power light to go out, or are you shutting the lid with the window still on the screen? It's possible that you're putting it to sleep before it shuts down (as I know the default operation of shutting the lid is to sleep the laptop, but what I DON'T know is what happens if you shut the lid while the shutdown window is up - ie: whether it completes a shutdown or sleeps mid shutdown)?

OP is probably not giving it ample time to shut down and then closing the lid just makes it sleep.

Thanks guys for your reply
I do get a window with a countdown.
What I do is click the shut down button, the screen goes black and I close the lid.
Still the light remains on.
I can't get it to restart too.
I was on the phone with an apple technician and I am reinstalling mac os x as he asked me to, and see what happens.
I ll get back to you later.
thank yoiu again.

Ok guys, I reinstalled the system.
The restart function seems Okay now.
However, the shut down still causes problems sometimes.

@Nethfel, it doesn't even sleep. I don't know what that state is (zombie I guess :d), but the screen gets black and you cant turn the compuetr on. You have to force it to shut down by holding the button pressed, and then switch it on. Subsequently, I get a message: "Mac OS X quit unexpectedly" or sth.

Any ideas?

That's weird. Unfortunately, I don't know enough about all of the running processes or shutdown order to comment further. Maybe something is running that isn't exiting properly when issued the shutdown command and it's causing the computer to hang mid shutdown? Maybe someone with more experience can chime in, but maybe a reset of the SMC? (see: Apple Portables: Resetting the System Management Controller (SMC) )

I would imagine it would be the same with a Macbook but on my aluminum iMac when I shut down I click on the apple while holding down the option and command buttons and then click shut down and it by passes the pop up that tells you that it will shut down in so many seconds. It goes right to shut down.

So I googled the problem (silly of me to not do that from the get go as I was expecting myself to be the only one in the galaxy to suffer this problematic), and as it turned out it s a frequent problem related either to Leopard itself or Leopard running on the new aluminum macbook machines.
I didn't, however, stumble upon any way to resolve the issue... yet

That's odd, I have a macbook aluminum 2.4ghz, and haven't had that problem..

@Nethfel: thanks very much for your concern and your attention
I have the same product as you... Could you please tell me if you suffer any heat issues?

I say take it to Apple Store and demand a new one.....my brand new 13" Macbook Pro has none of these issues....

Thanks man ... I just don't give up that easily...
I think I was able to sort that out.
What i did is I deleted a file called apple.loginwindow.plist contained in Library under the root directory.

Later