Wouldn't that be /Users/username/Photos and look for 'iPhoto Library'? Ksmak, I think looking for the above named file is an okay idea to verify it's still there. Then back it up. Think about how you'd feel if you lost all your photos. It happens. Before it happens to you, find a way to make at least one other copy. Mine is 10 gigs, so it won't fit on one DVD. There are several ways to back up your computer, including Time Machine that comes with OS X 10.5 Leopard. If you have 10.5, you can back up with Time Machine by attaching an external hard drive. You can get them from your favorite electronics store. Plug it in and your Mac will ask you if you want to use it as your Time Machine drive. The hard drive does have to be formatted as a Macintosh drive for Time Machine to work. I think it will automatically help you do that but I'm not sure. If it doesn't, run the program called Disk Utility in /Applications/Utilities. Click the picture for that new hard drive on the left side of the Disk Utility window, click the 'Erase' tab (WARNING, this will ERASE everything on the drive), and click the 'Erase' button (Mac OS X Extended journaled). The real question is what happened to the iPhoto application (the program itself)? If you have an iLife disc (iPhoto, iDVD, iWeb, Garageband), which you would if you had actually gone out and bought iLife from the store, go ahead and reinstall it. In other words, put it in your DVD drive and double-click the DVD icon on the Desktop. Then double-click the installer. Reinstalling iLife should fix your problem. If you don't have an iLife disc, install from the Applications DVD that came with your computer. Maybe you only got one DVD; if so, it should be on there. Reinstall the applications, which should include iPhoto. Let us know how it goes.