Hi iFriend,
try this, it worked for me:
1) first of all, uninstall QuickTime and older versions of iTunes from your PC, using the "remove" button in the "install applications" tool that you find in the windows control panel.
2) reboot the system
3) turn off the windows firewall application; go into the windows control panel, double click on windows firewall and disable the firewall option
4) if you have one, disable your Anti-Virus application; i mean its real-time protection.
5) probably it's not necessary, but for being sure... download and launch the
standalone installer of QuickTime (latest version)
6) download and launch the iTunes + QuickTime installer from this
web address
7) as an option, i suggest you to download and install also
iTunes Art Importer. It's a nice application, that allows you to import from the internet directly into iTunes the album ArtWorks of the selected tracks in iTunes. I installed it, and it works very well with iTunes 6.
8) after all the installations, remember to enable both firewall and anti-virus previously disabled!
as i said, probably the 5th passage is not necessary, but i did it and it worked!
if you have any questions or feedbacks, just relpy to this topic. stay iTuned! 🙂
bye, bye,
Marco