Nonresponsive partition table during install

I started a Ubuntu install, but "some user did something" that resulted in an install failure.

We can progress to the partition table, but now there are no clickable actions in the partition part of the installation. "Install Now" returns the message, "No root file defined."

How can I use Ubuntu from CD to make a root file or bootable partition?

have you tried a tool such as partedmagic?? If you haven't, try it and wipe the disk (or if you have some data you want to save select the recover disk option that MAY help in your case depending on what IT did) If that doesn't work run the following command:

dd if=/dev/zero of=/dev/sdx bs=512 count=1

Where sdx is your corrupted drive.

This will wipe the MBR and partition table. Just make sure you run this on the right drive.

The output will look something like this:

SunGod@linuxpc:~$ sudo dd if=/dev/zero of=/dev/sdx bs=512 count=1
1+0 records in
1+0 records out
512 bytes (512 B) copied, 0.0105726 s, 48.4 kB/s