You need to be at Service Pack 3 level before you can use Windows Updates.

To determine which service pack is currently installed on your computer, follow these steps:

Microsoft is not planning another big update to Windows 8, like a Windows 8.2 or Windows 8.1 Update 2. New features, if available, will instead be pushed via updates on Patch Tuesday. Latest Microsoft Windows Service Packs (Windows 7, Vista, XP).

1. Click Start, and then click Run.
2. Copy and paste, or type the following command and then click OK:

winver

A dialog box displays the version of Windows and the service pack that is currently installed on your computer.

If you haven't already, you'll need to install SP2 and then SP3 (note SP1 doesn't exist anymore).

How to obtain the latest Windows XP service pack
http://support.microsoft.com/kb/322389

SP2 - http://www.microsoft.com/en-us/download/details.aspx?id=28 (for single PCs also)

Detailed installation walkthrough for Windows XP Service Pack 2
http://support.microsoft.com/kb/875364

Microsoft Windows Xp Update Download

Steps to take before you install Windows XP Service Pack 3
http://support.microsoft.com/kb/950717

Windows Updater Software

Noted in 'How to obtain the latest XP service pack' is -

If you have problems obtaining the service pack from Windows Update, you can download the stand-alone update package from the Download Center. This page will say that this installation package is intended for IT professionals and developers. However, you can safely download this file. The following file is available for download from the Microsoft Download Center:

Also see: http://support.microsoft.com/kb/2497281
You may be unable to access the Windows Update website from Windows XP, Windows 2000 or Windows Server 2003