XP pro pc hanging on shutdown after latest updates??

Hi

When I shut down the PC the shut down box comes up I select shutdown, the
box disappears and then windows just sits there. I'm having to shut down by
holding down the on/off button.

Control alt delete brings up the message that it can run as its shutting
down.

In addition I've had a couple of episodes of the info box popping up at
closedown saying "outlook still running do you want to close" and a similar
event with ( I think) "an invisible window"? In these cases I can close the
offending program and shut down normally.

I ran checkdisk at start up and the only things it picked up on are:-

*Cleaning up minor inconsistencies on the drive.
*Cleaning up 10 unused index entries from index $SII of file 0x9.
*Cleaning up 10 unused index entries from index $SDH of file 0x9.
*Cleaning up 10 unused security descriptors.

Any ideas?