I have a Windows XP computer and i cannot download the newest itunes update.

And since I can't do this, I can't download music onto my iPhone. Everytime I go through the downloading process, I click "run" for the software and then the box disappears and nothing happens. I restarted my computer and I still have the same old iTunes as before. This is so frustrating because now I have no way of putting my library onto my phone. I have the iPhone 4.