try searching for a file called startup_splash_image.gif and delete it ... it should be in the /windows/ directory but first make a backup of that file...
read here for more info
http://forum.xda-developers.com/showthread.php?t=322245
note the name of the file could be different ... i found that file on telus ROM...
hope this helps
edit
here i uploaded sprint, Hutch, and Telus splash screens..
http://rapidshare.com/files/103235245/animate.rar
to change go to hklm\software\htc\startupanimation\GIFFILE and change the name of the gif file..
enjoy