what's the script to install/configure X?

[Rick Berger]

Just tried my first installation of Ubuntu, forgot my video card type, 
so I did an Alt-F2 to login and did a "lspci", but then couldn't get 
back to configuration script. So rebooted and I selected the wrong video 
card. System re-downloaded all the packages again, this surprized me and 
someone might want to check into it. Altough everything installed, I 
need to configure X. What's the script to do this?

Rick