problem downloading itunes and quicktime

I have a new ipod and I have to upgrade itunes and quicktime to the latest version. It will not download quicktime as it says an older version is already on my computer and I must remove it first. I have XP and I have tried to do this through add and remove programs but nothing happens. The name quicktime remains but there is no other information i.e. size of file. If I search for quicktime it find loads of files but will not let me delete them. Any suggestions.