I'm trying to update WoW on my brother's computer and can't download the patch. This is because something crashes during the optimisation process. It's got past the tools, but now when it tries to optimise the red progress bar will stay at nothing for a few seconds, then skip forward a few millimetres before instantaneously bringing up a windows error message that says Blizzard Updater has crashed. I've tried using repair, running in admin mode etc and it still does the same. How do I fix it? Is there a way to skip optimisation so I can see whether that's what's causing the problem?

here is the crash details from the error message for those that can make sense of it:

Problem signature:
Problem Event Name: APPCRASH
Application Name: Blizzard Updater.exe
Application Version: 4.2.0.4870
Application Timestamp: 4f19e111
Fault Module Name: Blizzard Updater.exe
Fault Module Version: 4.2.0.4870
Fault Module Timestamp: 4f19e111
Exception Code: c0000005
Exception Offset: 000b05c4
OS Version: 6.1.7601.2.1.0.768.3
Locale ID: 2057
Additional Information 1: 0a9e
Additional Information 2: 0a9e372d3b4ad19135b953a78882e789
Additional Information 3: 0a9e
Additional Information 4: 0a9e372d3b4ad19135b953a78882e789