I've been stuck now for over an hour. The progress indicators have not moved a hair.

Will closing them to try again screw it up?

Thanks :)

Mine did that too. I'm not saying yours isn't stuck, it very well could be. Just go get some breakfast... call your mom... distract yourself for a couple of HOURS. Hehe. Your configuration is unique and may result in odd behavior no one else gets and long pauses like this... let it do its thing.

Meanwhile, if it stays stuck, it won't matter if restarting mucks up the process, you'll still have to do that. Sorry... I hate system updates.

SP1 & 2 went quickly and without a hitch... this one's a doozey. Since I can do other stuff I'll just let it run... and maybe it will be done by Christmas :)

Are you trying to install from Windows update as I've had issues with SP's via this method.
I find getting the stand alone installer works a lot better.
Download details: Windows XP Service Pack 3 Overview