Not sure if this is the right section.

I have a desktop with snow leopard i have tried to use boot camp but keep getting the message.

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 using Boot Camp Assistant again.

1. what am i backing up my data that i have put in over the last few months.

2.In the disc utility there are all sorts of things in there what am i trying to reformat

Please help