Does dual booting erase hard drive?


If I dual boot another OS with Windows 7 will the windows 7 hard drive partition be erased? Is it necessary for me to back up all my files, and when I use the Windows 7 recovery disk is put in and I repair Windows 7, will all of my settings be erased? Thanks!
When you install another OS, there's no danger to your existing OS as long as you don't instruct the install to overwrite the partition that's already in use.
People have been known to do that through carelessness and poor preparation, but nothing in life is safe if you don't do it properly.
Create the space you need and label your partitions unambiguously before you start a new install, and you shouldn't accidentally do something you didn't intend.
If you have a lot of identically sized unlabelled partitions, that's when you might get confused about where you're putting things, so plan what you want to do first.
Post your plan of action and we'll advise you if you're doing anything wrong, or if you could do it better.