So I had a 32gb Windows XP partition that I want to upgrade to Windows 7. I removed the partition via Boot Camp assistant, and when I tried to make a new partition, it's telling me that I have to "Back up the disk and use Disk Utility to format it as a single Mac OS Extended (Journaled) volume. Restore your information to the disk and try again." What does that mean? Do I have to reformat (and subsequently erase) everything on my harddrive? If I have Time Machine set up, will I be able to bring everything back to how it was originally?