There are 9 different versions of iPhoto and they run on seven different versions of the Operating System. The tricks and tips for dealing with issues vary from version to version and OS to OS. So before anyone can help, they need information to work with. Basic stuff:
- What version of iPhoto.
- What version of the Operating System.
- Details. What were you doing when the problem arose?
- Did it ever work properly?
- Are there error messages?
- What steps have you tried already to solve the issue.
Anything else you can think of that might allow someone else to understand your issue.
With this kind of information somebody can develop a starting point for troubleshooting the issue.