ctht,
To uninstall it you need to delete the folder from the Program Files folder then open regedit and got to
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Curr entVersion\Uninstall. You will find a series of subfolders with alpha numeric names like this {7784A172-61F1-445E-8368-601607E0DD22} click on each one until you find the entry related to MP3 Player Utilities 3.68 displayed in the right panel, then delete this folder. Then do the same here HKEY_CURRENT_USER\Software\Microsoft\Installer\Pro ducts\
You should now be able to install a new version.
If 3.68 is not working for you and your player is 1.5 then try using version 4.0
HERE. Once you have it installed go to the AMV Converter folder and open AmvTransform.ini in notepad and change CHIPTYPE=0 to unlock the 1.5 settings.