lugo was giving a list of commands to enter into the terminal.
Unless I misunderstood, he suggested that you:
Boot to the Ubuntu live CD
Do Not install
open the terminal
info coreutils 'shred invocation'
to understand more about the shred command
to view a list of mounted drives.
then, carefully, use shred as outlined in the man pages to shred /dev/sd* where sd* is the 1TB hard drive you wish to erase. dd also has a function to overwrite with all 0s, but I recommend you read up before doing anything as these are powerful commands that can't be undone.