Stop XP from nagging about updates

I got down to the step to rename the folder Catroot2 to Catroot2.old. I get a msg box saying- Cannot rename Catroot2: Access denied. Make sure the disk is not full or write-protected and that the file is not currently in use.
I looked at the properties and there is a square box in the Read Only attribute. I cleared the box and clicked Apply, choosing all folders. I checked Properties again, but the Read Only attribute still has the square box there and I can’t rename the folder to Catroot2.old. Any suggestions, please. Thanks.