tell me about it!! It popped up in my tray to update and before i could see what it was the download began (stupid auto-updater). when i tried to Un-install it gave me trouble with simple programs like Magic Tune and even my MOUSE software, COME ON!! I couldn't even remove some of the redundant tray icons that appeared after way too many times trying to Un- and then RE-installing my drivers for my mouse, monitor and USB devices!! Speaking of extra icons, after removing SP3 for the final time (that's right, I actually tried 3 times, once with a tech-guy from Microsoft remotely using my PC) there were 3 ADD/REMOVE PROGRAM icons in Control Panel!!! Anyway, this all could have been prevented by changing your Automatic Update feature, START>CONTROL PANEL>AUTOMATIC UPDATES. Change the option from AUTOMATIC(recommended) which automatically downloads and installs updates, to the second option that automatically downloads updates but lets YOU choose when to install them. As for redundant Control Panel Icons (add/remove programs) just search appwiz in C:\ and remove any that say (2) or (3) after them. ie appwiz.cpl(2) and leave appwiz.cpl alone.
My recommendations would be NOT to install Service Pack 3 for a couple of months until they work the bugs out. And if you have, remove it if you can do it safely. I created a Restore Point prior to installation so i was lucky. There really doesn't seem to be many advantages to the new update anyway so don't sweat it. Sorry to Ramble but I wish somebody had posted such a comment for me before i updated!!