Where can I download Windows XP Service Pack 1/1a?
Update - SP2 is out
On August 9, 2004, Microsoft released SP2 for Windows XP. SP2 is the latest collection of updates for Windows XP.
If you still need SP1/1a
On February 3, 2003, Microsoft released SP1 again as SP1a. Just like SP1, SP1a is a collection of updates for Windows XP. Windows XP SP1a is the same as Windows XP SP1 except that the Microsoft virtual machine (VM) is removed in SP1a. There are no other changes or fixes included in this update.
The service pack is a collection of updates for Windows XP. These updates address:
Security issues (including the Windows XP Update Package)
Operating system reliability
Windows XP Setup
Note: If you have not yet installed the Windows XP Update Package, you only need to install Service Pack 1 because the security update is included.
If you are not running Windows XP SP1, install SP1a to make sure that you have the latest security and reliability updates for Windows XP. Install any appropriate security updates and hotfixes that are already released or that will be released after SP1 on Windows XP-based computers that are running SP1a. Windows Update will continue to offer the same set of updates for Windows XP-based computers that are running either SP1 or SP1a. To download SP1 for Windows XP:
The Network Installation is ideal for IT professionals installing SP1 on multiple computers.
SP1 Express Installation (typically ~30mb)
Use the Express installation if you have only one computer to upgrade to SP1. Get more information about SP1 and instructions on how to install it. The Express installation checks your computer and installs only the files that are necessary to bring your computer up to date. As a result, the number of files installed and the time required may be less for computers that already have Windows XP hotfixes installed.
Visit the Windows XP SP1a official web site