When attempting to install iTunes, a message may display stating that the setup program is "not a valid Win32 application." This occurs because the download is incomplete or corrupted. Those with dial-up Internet connections are at the greatest risk of experiencing this issue. Removing all remnants of the corrupted download enables you to download iTunes again and install it successfully.
Hit the "Windows" and "F" keys on the keyboard simultaneously to bring up the Search window. Search for "QuickTimeInstaller.exe" and "iTunesSetup.exe," without the quotes. Delete all copies of both files.
Open Internet Explorer. In this window, click "Tools," then click "Internet Options." Click the "General" tab. Under the "Browsing history" category, click the "Delete" button. This removes all of the temporary files Internet Explorer saved, and may take several minutes on slower computers.
Close Internet Explorer and then reopen it. Browse to the iTunes website and download a new copy of iTunes. The copy should install without any difficulty.
If you are unable to download iTunes through Internet Explorer after several attempts, and you do not have a dial-up Internet connection, try using another browser such as Firefox or Safari. Both browsers can be downloaded at no cost.