ubuntu doesn't shut down

[renaaj at optonline.net]

> Great. i didn't know the installer was so helpful.  I just did it 
> and it seemd to work smoothly until i tried to shut it down.  I 
> shut down my laptop using ubuntu and the laptop screen seems to 
> power down but the laptop says on...and then i push the power 
> button on the laptop and it doesn't turn off.  i have to remove 
> the battery to turn it off.  i am going to uninstall and re-
> install again to see what happens...but is this a known issue?
> 
>

Anyone have an idea on this?  I installed ubuntu again and yet again the act of selecting shutdown from ubuntu (1) doesn't power down the laptop, (2) it renders the laptop's power button useless, and (3) I have to take the battery of the laptop in order to turn it off.

Thanks.