Trouble removing application from computer to re-install it

[nightingale61]

I'm unable to remove the Spotify player from my computer in order to re-install it. When I try to uninstall from the roaming data it comes up with "the folder or file being open in another program" when it is not. And when I try to re-install I get "the installer is unable to install Spotify because to be written are in use by another process. Please make sure Spotify is not running and retry. (Error Code: 18)" I have even gone as far as going to the control panel and using the program uninstallation program. Is there any way for me to fix this situation? Please help ASAP.