100s of millions of XP users have successfully upgraded - most using Windows Update. Unfortunately, if only 1/10 of 1% fail, that's still millions of broken computers.
And millions of broken computer users make a lot more noise than 100s of millions of happy users who tend to make up the not-so noisy "silent" majority.
Some will say that XP SP2 "fully updated" is the same as SP3. It is not. Updated as far as
SP2 allows is not the same, or as good as, updating the
operating system. SP3 is the latest "updated" version of XP. If you are running XP SP2 regardless how current, you are behind.
XP3 changes some default settings and has a few other subtle additions and changes/enhancements not part of a fully updated SP2. One, sadly, removes the Address bar option from the Taskbar. Fortunately, a tweak came to fix that.
There were also some welcomed security changes - not many, but enough to where if you have not upgraded, you are behind. See Microsoft's abstract,
Overview of Windows XP Service Pack 3 (a TinyURL Redirect) for more details.
I recommend you review the MSKB Article 950717,
Steps to take before you install Windows XP Service Pack 3.
I personally prefer doing major updates locally, either from an install file on another drive, or by disk. You can use the network install file from
here, or order the CD for a small shipping & handling fee from here:
Windows XP Service Pack 3 Network - ISO-9660 CD Image File
Windows XP Service Pack 3 on CD - Asia
Windows XP Service Pack 3 on CD - Europe and Africa
Windows XP Service Pack 3 on CD - North America - about $10.
Windows XP Service Pack 3 on CD - South America