Windows update issue?

[Powerstroke2000]

My PC's Windows XP "update" keeps telling me to update upon reboot, and when I do it seems to go through the process...but stops half way through and stops. There is a progress bar as to where the upgrade is...and each time I try to do this upgrade, I get this same progress at about the half way point, and it won't go any further!
It is like it locks up too, as when I click on the "X" to get out of the update....it just won't happen, and a reboot is the only way to start from scratch again.
I've gone through this process 6 or 8 times over the last month...all with this same result, and thought I would ask what I might be able to do to get this update to finish it's process??

I keep just giving up...but occasionally will re-try the process, always with this same result, and it's very frustrating.

Thanks in advance, on any suggestions/advice!