How do you un-install without a disc?

Question

I have a mac BookPro i bought Feb 2011and never updated the OS, until i bought Mountain Lion and for some reason it's not going to port over anything from iPhoto, which is about 2k pictures etc.  i want to uninstall the OS and i do not believe i have a disc from the previous OS to reinstall.  Is there a way to revert back to original OS without the disc and not lose any pics, movies, music etc?  This OS upgrade is more trouble than it's worht actually and wish i never spent the money on it.  thanks in advance for your help.

Answer 1

Simple solution:
Make a duplicate of your iPhoto Library and give it a new name. Upgrade iPhoto. When you first run the new iPhoto it will automatically update your iPhoto Library (but not the copy.)
If you do not maintain backups you risk losing valuable data. in fact make multiple backups.
Basic Backup
For some people Time Machine will be more than adequate. Time Machine is part of OS X. There are two components:
  1. A Time Machine preferences panel as part of System Preferences;
  2. A Time Machine application located in the Applications folder. It is
      used to manage backups and to restore backups.
Time Machine requires a backup drive that is at least twice the capacity of the drive being backed up.
Alternatively, get an external drive at least equal in size to the internal hard drive and make (and maintain) a bootable clone/backup. You can make a bootable clone using the Restore option of Disk Utility. You can also make and maintain clones with good backup software. My personal recommendations are (order is not significant):
  1. Carbon Copy Cloner
  2. Data Backup
  3. Deja Vu
  4. SuperDuper!
  5. Synk Pro
  6. Tri-Backup
Visit The XLab FAQs and read the FAQ on backup and restore.  Also read How to Back Up and Restore Your Files. For help with using Time Machine visit Pondini's Time Machine FAQ for help with all things Time Machine.
Although you can buy a complete external drive system, you can also put one together if you are so inclined.  It's relatively easy and only requires a Phillips head screwdriver (typically.)  You can purchase hard drives separately.  This gives you an opportunity to shop for the best prices on a hard drive of your choice.  Reliable brands include Seagate, Hitachi, Western Digital, Toshiba, and Fujitsu.  You can find reviews and benchmarks on many drives at Storage Review.
Enclosures for FireWire and USB are readily available.  You can find only FireWire enclosures, only USB enclosures, and enclosures that feature multiple ports.  I would stress getting enclosures that use the Oxford chipsets especially for Firewire drives (911, 921, 922, for example.)  You can find enclosures at places such as;
  1. Cool Drives
  2. OWC
  3. WiebeTech
  4. Firewire Direct
  5. California Drives
  6. NewEgg
All you need do is remove a case cover, mount the hard drive in the enclosure and connect the cables, then re-attach the case cover.  Usually the only tool required is a small or medium Phillips screwdriver.