Laptops and iTunes?

[m1spw]

I got a Dell laptop for Christmas and with having just over 4GB of music in iTunes format I wanted to get iTunes onto my laptop as soon as possible. I have tried downloading it from the web twice and installing it, and once from the CD that originally came with my ipod, but neither installations have worked. It seems to work, the files load up and the icon appears on my desktop, but then when I try and open it nothing happens.

And then if I try to switch my laptop off it takes ages while it stops the program from doing something. Anyone had experience of this, or know what to do?