iPhoto crashes my mac.

Every time I try to open iPhoto the whole mac freezes for hours, and it won't respond to anything I do. It just happend one day and now I don't know what to do. It's been like this for a while now. If I even try to open somthing that's connected to iPhoto my computer will stop responding 100%.
It's so bad that I even considered bying a new paltop.