Let's Get Started
The process of updating to Windows XP Service Pack 1 is not as difficult as you might imagine. In fact, it is fairly simple actually.
Step 1 - First of all you will need to download the 133mb Service Pack 1 file from the Internet ready for installation, if you can find a working mirror anywhere. I would have recommended you getting it from Microsoft servers but from the time it took to write this guide Microsoft pulled it from their Premier Download section. So, here are a list of mirrors I have found that work at time of writing this guide - Keep trying, one of them will work eventually.
As we find more mirrors we will add them here, if you know any others please do us a favor and email us with the details!
If you have no luck finding the file, alternatively you can wait a few days till Microsoft officially release the Service Pack to the public.
Step 2 - Once you have downloaded the file you will need to also go ahead and download the sneaky Windows XP serial key changer - This is the program which makes the installation of Windows XP Service Pack 1 possible for you naughty folks out there that use an illegal copy of Windows. If you don't change your serial key you'll get booted out of the install process half way through with the following error message.
Of course, if you are one of those good folks who have a legit version of Windows, you can skip this section and jump straight to the installation of the Service Pack. The program we will use to change your serial key is readily available all over the Internet - Microsoft asked us a few days to remove the file from our servers, but a friend offered to host the file on his servers for us. Download the Serial Key Changer program and Viewer here.
How much to upgrade to x64 Edition?