1) Just download Google bootanimation.
2)first rename the Google boot with the name of you devices boot animation such as:hTC_boot.zip,bootanimation.zip,or etc find the files under system>media or system>customize>resource or else.
NOTE:"differnet devices are having different paths to boot and down animation.zip files...find it yourself or ask someone!
4)AND you are done now just reboot your device to see Google boot animation and hit the thanks button!!
Google BootAnimation For Htc Desire X