XP SP3 Install problems

[Whyzman]

I'm having problems installing Service Pack 3 on the kids' computer. MS Update has tried to install and failed. I did a Windows repair and tried again. It makes it quite a way through, and then give me a "Service Pack 3 setup error. Access is denied."

I'm assuming that SP3 is essential to keep up with critical security updates??

Anyone else encounter this perplexing problem??

[Whyzman]

Success!!

I followed the Microsoft registry fix with the .cmd and followed that up with the XP 3 install and it went through...