SP3 only includes updates up to April 2008. You should manually install:

First, confirm you are actually on SP2.

In the modern era of solid-state drives and cloud computing, Windows XP feels like a relic of a bygone age. Yet, for many users, legacy systems remain critical. Whether you are maintaining an industrial machine, running specialized legacy software, or simply reviving an old retro gaming rig, keeping the operating system stable is essential.

Have your XP SP2 CD ready to restore missing files. Then retry SP3.