javad'
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.
I would say that on the other computer you are logged on with a limited user account.
Just a note 3.68 is far more stable than 4.0 so if you have a 1.5 LCD player you should stick with 3.68
If you have a 1.8 then use 3.57 setup as posted here
http://www.mympxplayer.org/full-scre...or--vt449.html