You must be careful when adding boot screen. The file must me compatibile with your Xp version, I know cause there can be found sp1 and these days maybe even sp3 prerelease boot screen. Be careful. And also make a backup before you take any replacments in your root directory. You can also edit startup.ini file latter when you check and see yourself that it's working fine. Startup.ini can be adressed throug sys propertes\advanced\startup and recovery\settings