Where can i get a copy of OS X Lion s/w?
If your Mac originally came with OS X Lion, is capable of doing internet recovery, and you have a WPA/WPA2 network, then booting using Internet Recovery will enable you to install OS X Lion. To boot into Internet Recovery, follow these steps:


Shutdown your Mac
Press the power button
Quickly release it and hold down Command-Option-R
Keep on holding it until a globe shows up, or a list of WiFi networks.
For more assistance, visit https://www.apple.com/osx/recovery/


If that is not an option, you can purchase the OS X Lion download code from here. Upon recieving it, go to the Mac App Store and redeem the code. It will download like any other app. If you are installing it on a Mac running OS X 10.8 or later, you will need to create a bootable USB and wipe all your data, as the installer will not allow you to install 10.7 on a newer OS release. If you choose this way, be sure to make a copy of the Lion Installer and backup all of your files.