Problem during shut down

Hi,
Sometimes when shutting down my Macbook i find that the monitor/HD etc appears to switch off but the green light on the right hand side of the front of the computer continues to flash

The computer will not restart until i hold the power button down twice for a few seconds each time

When it finished loading OSX tiger i receive a message telling me that it did not shut down properly last time...

This does not happen all the time, but it is just pretty annoying- very PC like....

Any ideas?

How exactly are you shutting down your MacBook?

I'm just clicking the apple icon in the finder then "shut down"
then "shut down" again when the dialogue box appears

I imagine this is the normal way of shutting down (not meaning to be a smart ****, i'm new to the world of macs as you can tell by this post)

Yeah, that's the way you should do it. What needs do you have to shut down the MacBook? You can put it to sleep by just closing the lid. It will last in sleep mode for a couple of days.

well i guess because if should work properly and i don't want to leave it on all the time....

try to reset PMU (power management unit)

1. shut down (somehow)
2. disconnect charger
3. remove battery
4. hold dawn power button for 5-7 seconds
5. insert battery
6. plug in the charger
7. push the power button to start up

Are you closing the lid before it has shut down?