Can't install Ubuntu on my Windows 7 laptop

view story

http://askubuntu.com – I tried installing Ubuntu in two different ways: First, I tried the Windows Installer, and it goes well until I reboot the system and, when booting on Ubuntu, I get the error: No root file system defined. Second, I uninstalled wubi by going to to Control Panel -> Uninstall Programs -> Ubuntu. Then, I booted the laptop from the live CD and selected install. It boots okay but in the screen right after the one that says to make sure you have 4.5 GB available, Internet connection, etc, when I click continue it throws me a message saying that Ubuntu had an internal error and asks me if I wa (HowTos)