I need help please,iPhoto 9.6.1 will not update

Good day all, I have a 2007 iMac and have up graded my operating system to Yosemite about a month ago. I have had no problems until today. I tried opening my iPhoto and it say cannot open iPhoto and that I need to download version 9.6.1 in order to work. I try downloading and it tells me that it is installing, but nothing happens. I left it for 3 over hours and nothing. It just seems to hang there. I have shut down the computer and tried to re install and the same thing happens.

Any suggestions on how to fix this? I am not very technical at all so I may have to make an appointment at the Apple store.

Thanks for the help,

via ehMac.ca http://ift.tt/1IRILWU