Can you copy the Itunes application from one computer to another?

So I recently got an Iphone and I went to install itunes into my computer. The installation bar would reach the end but never let me continue - just the cancel bar would still be clickable.

I then noticed in the All programs (Windows 7) that it said "Apple software update" when clicking on it - it said "The Parameter is incorrect" so I can't progress further.

I've tried uninstalling itunes and redownloading. I don't know what to do. However my sister has itunes installed to her computer (Same make/model of pc) So I was wondering if I could copy over the application using USB? Or if not, how can I fix the parameter problem?

You can register 5 apple products to one Itunes account so yes you can install Itunes on different machines

Clear all references to Itunes from your PC through your Control Panel (if its there) then download and install Itunes on your PC in the normal way.
Whilst writing I would point you towards syncios a far better free program for putting stuff on and off Iphones, Ipads, Ipods etc. You don't need a college degree to use it as it is user friendly unlike that heap of siht called Itunes.