problem with expose & dock & dasboard

I got a new macbook 3 weeks ago but yesterday expose and dock froze so i couldnt change windows or use expose. f9 f10 etc all wouldnt work. same with the dock and dashboard. They simply wont open or respond. The other funtion buttons (eg volume brightness etc) work. I tried force quit but it does nothing.
I then pressed the power button but it did nothing so i had to take the battery out to turn it off.
I turned it back on and everything was fine.
Then it happened again today earlier, power button but nothing happened so battery out etc again.
Now i has happened again now. This is really annoying. Does anyone know a cause for this?
The thing is verything else is running. Its just expose, dock, dashboard & power i think.

Anyone have any solutions?
Has this happened to anyone else?

 

sorry i didnt descirbe the turning off thing. i can go to shutdown and press it but it just freezes on the picture of the desktop.

How do i do that?

 

I repaired the disk utilities and verified start up disk two days ago and it seemed to be fine but it happened again 5 minutes ago. I had firefox, msn and itunes open which is in no way too strenous for my mac and all of a sudden expose, dock and dashboard wouldnt open or do anything. I couldn't hide windows or do anything and when i went to shutdown it froze just before the final shutdown stage and i had to take out the battery again.

I haven't tried creating a new account.

I'm not sure what's wrong with it. My macbook is only 1 month old.