Ubuntu has a very beginning user friendly interface.
http://www.ubuntulinux.org/

Mandriva has that too, but has a lot more applications, like grafics making apps.
http://www.mandriva.com/

Im using Ubuntu by the way, so if you have any questions about it, just pm me.
Ubuntu has a live cd too, that way you can try it on your windows machine save and with out losing your files.
Just reboot your system with the live cd in it. Make sure in your bios that your machine looks for a bootable cd first.

Good luck with it.