I  was trying to install  iTunes for Windows 7 64bit on my desktop computer,  and while the download was not corrupt, I was getting an error message. The error message was something like, "Error, this computer is not customized "  , or something to that effect.       I was about to return my new iPod back to Best Buy because of this - since the main reason I bought it was to play mp3's and videos on it and to do that I need  iTunes

At my wits end, I said a prayer- and it then suddenly occurred to me that Windowblinds may have something to do with the problem.   I opened Windowblinds and applied the original Windows 7 Aero skin from the list   then tried the installation again with no problem this time.   

So if anyone is having similar problems with the iTunes installation , they may also find it then works if they temporarily apply the original Aero skin before trying the exe. installation file again.