iPhoto

Which version of iPhoto do you have? And which version of MacOS X?

With Mac OS X, version 10.10.4 you need to update iPhoto to version 9.6.1

The problem is, that these updates are only available from the App Store and not from Apples Support Downloads page.

But because Apple stopped selling iPhoto, the AppStore does no longer offer iPhoto updates.

You can only update by reinstalling iPhoto from the Purchases history at the App Store. Sign into the AppStore with the AppleID you used to buy iPhoto or update it in the past. Move your incompatible iPhoto to the Trash, but don't empty the Trash. Then Reinstall from the fourth tab (Purchases). (the method is described in this user tip:

Get iPhoto 9.6.1 if you didn't update before OS... | Apple Support Communities).

Just worried about the data inside it...user id and password is the same as my Mac.

Is it possible to remotely delete all data inside the iPad???

Did you set up "Find My iPhone" on your lost iPad? Then you may be able to lock it or erase it remotely, if it is online from the web interface at www.cloud.com . iCloud: Use Lost Mode

But after such a long time it is unlikely, that it still will work. Change the password for your AppleID immediately: What To Do If Your iDevice or Computer Is Lost ... | Apple Support Communities New

Can't recover back to the app store...maybe hide...can't unhide too...

If iPhoto is not in your purchases history, your version may be too old or it has not been associated with your AppleID: Are you using the same AppleID you used, when you originally installed iPhoto?

There is no way to update iphoto, if it is an old version that has not been purchased from the AppStore or associated with your AppleID at the App Store if it came preinstalled on your Mac.

So...can i still have chance to use iphoto app...???

Sorry, no.

Apple does no longer sell iPhoto. Only customers who previously installed a Mac App Store version of iPhoto can reinstall iPhoto from the Mac AppStore and update this way. The iPhoto installer DVDs that are sold at Amazon or eBay do not have iPhoto versions that are compatible with Yosemite or Mavericks. You can only use them for older MacOS X versions.

Use the new Photos.app instead of iPhoto. It will be improved with the next release in autumn, when the new Mac OS X 10.11 will be released.