According to an article at informationweek.com, the internet explorer version 7 from ISPs such as Comcast and Qwest may crash during the SP3 installation because they tend to be outdated.

The crash occurs because XP3 runs a dll file called XMLLite.dll and it is not compatible with versions of IE7 that were released before October.

“If you produce custom IE7 packages, then you need to ensure that those packages will install successfully on Windows XP SP3,” said Jane Maliouta to ISPs in her blog. She added that the ISPs can update their distributions by downloading a kit from Microsoft’s TechNet site.

Source: Information Week