Updating 10 4 8
You purchase the special download code for OS X 10.8 from here. Good Luck! I still use Snow Leopard and I have El Capitán on an external Fire Wire hard drive and I can see that drive, as well as as all of the data on that drive for El Capitán.
What exactly can't your Mac see of your El Cap install from OS X 10.6 Snow Leopard?
If you previously downloaded the last i Photo update (which is no longer available from the Mac App Store), then i Photo continues to work with Yosemite and you can choose to continue to use i Photo instead of the new Photos app.
If you don't have the last update of i Photo, any other version of i Photo will no longer work with Yosemite. Does that mean I can't run OS X 10.8 Mountain Lion? Not sure what specs are relevant but it's a white, early 2008, Mac Book 4.1, model MB402LL/A. The reason I ask is, it's running poorly, VERY poorly. And I just can't afford a new one or an expensive tech 'overhaul'.
now would be a good time to completely uninstall this apps by doing a Google search to learn how to properly uninstall these types of apps.
These types of apps will only cause your Mac issues later after the install of the new OS X version and you will have to completely uninstall these types of apps later.
You can use this update to upgrade your system software to version 4.85.
So, you would need to check to see if you have software on your Mac that maybe older than, say, 2006 or older. If you have any commercial antivirus installed and/or hard drive cleaning apps installed on your Mac, like Mac Keeper, Clean My Mac, Tune Up My Mac, Mac Cleanse, etc.
On a laptop that old, it is more likely that your hard drive is failing. when I try to install it says to get a new copy from the App store, but cant find it.
I have a variety of macs and MUST use Mavericks to be able to to access my drives with el Capitan.
Can any or all of your older software run on OS X 10.8 Mountain Lion?
Apple still has OS X 10.8 available for download from the Mac App Store using a special pay download code you input into the store to get to the Mountain Lion download/ install in the store.