An authorized Apple service provider could be found that will work on the older
MacBook Pro models that the Apple Store genius doesn't work on now.
You could get and study an ifixit.com repair guide for mac portables from their site
to see how complex the specific details of hardware upgrade in the computer may
be and also check elsewhere such as everymac.com for specifications to see if the
model you have can use more RAM and a larger capacity hard drive never hurts.
Hard disk drives have moving parts, so they will wear out. They're not very costly.
If you have a retail Snow Leopard 10.6.3 DVD install disc, and that can be used to
start the computer (if it shipped with a grey label Snow Leopard with newer version
the retail one won't work) + be able to erase and re-install a new system on HDD.
There is an update file for Snow Leopard 10.6 that is a download Combo file to
take that system to its last final step, Mac OS X 10.6.8 Update Combo v 1.1 :
• Mac OS X 10.6.8 Update Combo v1.1 - for use to update already running 10.6.
After the computer has a good installation of 10.6 Snow Leopard and is updated
to 10.6.8 v1.1 combo, there is this later article and update to that version, here:
• About the "Mac App Store update for OS X Snow Leopard "- Apple Support
https://support.apple.com/en-us/HT205702
This update is recommended for all Snow Leopard users.
If there are applications and other software items on the computer, and there is no
retail installer to restore them to an erased and reformatted hard drive, then you'd
have to purchase the retail counterparts from amazon or other vendors. iLife, iWork
and other applications suites were originally included in the new Mac and original
versions with the included OS X version were also on the grey-label install DVDs.
The grey-label discs are 'machine build year version specific' to that series of Mac.
You can repair the hard disk by using the Disk Utility version on the install DVD:
• OS X Snow Leopard: Using Disk Utility to Repair a Disk:
https://grok.lsu.edu/Article.aspx?articleId=9849
Same utility can be used to erase, reformat, and re-install basic Snow Leopard 10.6.
This article tells you how to start the computer from the installer and run the repair.
You may need to read up on specific other items. Time is much too late here for me.
Hopefully you can get the computer squared away, once it's updated to 10.6.8 it
can then see the Mac App Store, where you could look to see El Capitan.
Your model may run the latest OS X 10.11.3 OK, otherwise choices would be
ones you'd buy from the Apple Store (10.7 Lion or 10.8 Mountain Lion) and they
send a download code to redeem the purchase via the App Store. After installing
updates or upgrades, run the Software Update (or once you get the App Store
running, use it to see if any updates for present OS X exist; or upgrades to newer
OS X systems.) The Lion and Mountain Lion don't appear in the App Store list
to download, until you purchase their download code.
Newer iDevices would need Mac w/ newer OS X than Snow Leopard 10.6.8 to work.
Or if an older iDevice sees an upgrade to newer iOS system, the older OS X
won't be able to support the item. The iTunes store versions change w/ upgrade.
These can be confusing and at 2AM, they are details that I won't add here now.
Another world, past the install disc media to the online installer era, is upon us.
Good luck & happy computing! 🙂