I have an HP Desktop AMD 64 6-core processor 10GB RAM 1.5TB HDD and Windows 7 installed. I downloaded the 12.04 ISO and burned to a DVD.

I want to install Ubuntu over Windows. I have recovery CD's made in case Ubuntu isn't for me and my family. During the install it says No root file system is defined please correct this from the partitioning table.

In the box where I should be able to choose a partition, none are available to choose from, it is blank. I know that HP has decided to use 4 partitions. How do I go about deleting all the partitions using the LiveCD? I've never used GParted before and am a bit lost when it comes to anything to do with partitions.