How do a OS system repair on Win 7 With Reistallation Disk

(1)Can someone out there explain, backup and restore, (2)Repair Disk, (3)System image, (4)Where they reside on the computer,(5) Their differences,(6)How they relate, and mostly (7)How to do a System Repair on a Studio PC with Win 7 64 bit. I have a reinstallation disk. I'm very confused by it all. (7) Library got screwed up, and I wanted to reset them back to the way they were when the OS was first loaded. (8)What happens if I do a disk cleanup on the Recovery Drive, and (9)How do restore points enter into all this. (10)Should there be a "My Library" folder somewhere and where. I can't find any info on how this whole thing works start to finish, when to use what and why! I'd like to repair the OS without loosing or changing what's currently in the files and or folders. (11) What file do I download pictures into in order to keep Libraries straight. If my Recovery disk shows almost full how do I recover disk space. I know this is all related somehow.