system updates broken!

[Pogman]

I have a new MacBook, and am liking it very much - however I can't get the software update to work properly.
I may have interrupted the initial download of the recent mac OSX combined update, and now it seems unwilling to either download it again properly or intstall. After hitting the 'install now' button, it gets to 'configuring installation' and gets stuck there, unable to load anything further. I have left it to do it's thing for some time...
Is there some way of re-installing this update? Can anyone help?
Ta.

 

[Pogman]

...the recent iTunes and iPhoto updates seem to be fine, by the way.