Having problems installing Itunes to Windows 7 Computer

Hello, Can someone please help me!

I've tried installling Itunes to my Windows computer since I've now got an Iphone. However, When I go to install It reaches the end of the installation but never allows me to click "Next", the Cancel button is still highlighted.

If I click the cancel button, the update will not cancel. The box will just stay on the screen.

I then noticed that on the "All Programs" section, it said "Apple software updater" - When clicking on it, it said something about the "parameter incorrect." So it couldn't perform the action. I think this is the problem but I dont know how to get round it.

Could someone please give me a simple soloution!