"Lock up" when trying to install osx update 10.5.6

[Hira]

Hi guys.
First let me introduce me.
im a 23 yr old Man living in norway ,
and i just bought my first mac
a imac 20" 4gb ram "aso"
I love it. and i know im gonna be spending
some time in this forum so HI

Anyways . i am trying to install Combined Mac os X - update. 10.5.6
(Thats atleast the name for it Directly transformed from norwegian to english)

and when i try to run the update it ask me to reboot.
I press reboot and it closes all of my programs and
the update starts installing , but the progress bar stops when its like 20% finished , i`ve been waiting for 12 hours and still no progress...
Whats wrong ? what can i do ?
All help is apriciated.

Marius the imac noob .

 

[JediMeister]

Go into the Macintosh HD/Library/Updates. Clear out the contents, try downloading the update from the Apple menu again. If there is no change, i.e. the download/installation are not successful, download the 10.5.6 Combo update directly from here.