1 - Back up your iPhoto library,
Make a copy of the iPhoto library - and if you are always running backup software 9like Time Machine for example) you are 100% guarenteed to lose all of yoru photos sooner or later - if they hae any valuse to you you must start backing up ASAP
2 - Depress and hold the option (alt) and command keys - Take your finger and press down on the option and the command keys and hold them down until the first aid window appears after you do the next step
3 - and launch iPhoto - click on the iPhoto icon in teh Dock
4 - rebuild your iPhoto library database - click on the option in teh first aid window to rebuild the database and do it
The version of iPhjoto can be found using the about iPhoto command under the iPhoto menu - the version of the OS using the about this Mac command under the Apple menu
LN