Download UXtheme.dll Patch For Windows XP SP3
In spite of all the problems that have come with Windows XP SP3, people are still using it. If you are also one of them, then you must have noticed that your 3rd party Windows XP themes have not be working after installing service pack 3. That’s because the uxtheme.dll has been changed.
To fix this, you will need the UXtheme Patcher in order to run any 3rd party themes on Windows XP. Download it from here [direct link] and run the EXE file. Press the Patch button, and wait for a few seconds for it to patch. Now restart your computer for the changes to take effect.
If you would like to copy the uxtheme.dll manually, then download its the latest SP3 version from here [direct link] and paste it in C:\Windows\system32\ (Overwrite if needed). Restart your computer for changes to take effect.
Now you should be able to use 3rd party themes without any problems.