Xubuntu install, cannot install alongside Windows 7

I was installing Xubuntu 13.04 from a USB stick, and chose the "Install alongside Windows 7 option"

I re-sized the partition sizes to my choosing and pressed next. It hanged for a good 10 minutes which never happened from ANY of my distro installs, so I shut the PC off and booted up from USB again. Now when I try to install Xubuntu, ""Install alongside Windows 7" is NOT there. It is not my PC so I'm not going to delete W7. Why did that option disappear? How do I install Xubuntu now?

Thanks.