I haver a Mac (osx 10.5.8, Intel Core 2 Duo) with a Windows 7 Partition that I set up in Boot Camp. I would like to completely Replace the Windows partition with Ubuntu 12.04 (64 bit, i think). I have installed rEFIt. My question:

Can I boot Ubuntu from a CD in my Windows Partition, and just install Ubuntu in its place? or do I need to wipe the Windows partition and do some sort of reformatting first?

Thanks for considering.