You can download Windows XP Service Pack 3 here.
FACTS…according to WinSuperSite.com
“It is the final Windows XP service pack, a collection of previously-released fixes and product enhancements, as well as a few new features that are unique to this release.
You will need to install at least SP1 on XP before installing SP3.
SP3 does not apply to the x64 version of Windows XP. Instead, that operating system is updated via service packs aimed at Windows Server 2003
The new features, according to WinSuperSite.com:
Network Access Protection compatibility. Announced years ago, this feature allows Windows XP machines to interact with the NAP feature in Windows Server 2008. This functionality is built into the RTM version of Windows Vista as well.
Product Key-less install option. As with Windows Vista, new XP with SP3 installs can proceed without entering a product key during Setup.
Kernel Mode Cryptographics Module. A new kernel module that “encapsulates several different cryptographic algorithms,” according to Microsoft.
“Black hole” router detection algorithm. XP gains the ability to ignore network routers that incorrectly drop certain kinds of network packets. This, too, is a feature of Windows Vista.”
Of course, some people had problems after installing Windows XP SP3, which happens with every Service Pack or major update. SP3 will create a Restore Point, but the best thing you can do is backup your data prior to installing XP SP3, that way if anything happens, you’ll have peace of mind. Also, you can uninstall SP3.
Always do a complete scan of your computer using a reputable antivirus program, and anti-spyware program. Service Packs generally don’t play nice with viruses or spyware.
A known issue with SP3 can be found via eWeek.com (rebooting issue). Sound cards are known to not put out any sound after installing SP3 as well. Many other issues have arised, but the cases seem to be few and far between.