Iphoto disappeared completely

It started when i got a popup window all the time said somthing about my disk memory was full. I transfered my folder called ''Iphoto library'' to my extern harddrive (with about 150gb of pictures and videos). After that i still had full diskmemory so i decided to restart my computer and nothing happend exept from a logo i think it was an logo of an letter or somthing and it winked. Nothing happend so i restored my computer using CMD + R or somthing like that and i managed to restore it. I turned on my computer and Iphoto is completly gone. Not in finder not anywhere.. I opened up appstore to download it. There was no ''download'' it now said ''Accept'' i clicked and it asked for my password and i typed it in and nothing happens. I thought maybe if i update to mountain lion it will come back, so i did. Still have the same problem. It's gone. Not on my computer and can't download it..

Help anyone really need it!

(I use Mac book pro mountain lion (10.8.4) Intel core i5 with 500gb memory.)