Can't find recently installed Lion on hard drive!
I downloaded Lion for my MacBook Pro last week because my 2014 TurboTax disc needed at least 10.7. The machine has been slowing down considerably and so I asked a friend who is an IT guy to help me. He said defragging might be needed. I had already installed Lion when he said to make a bootable version on a thumb drive. I set about trying to do so but can't even find Lion on my computer! Can I only make a bootable version on a thumb drive if it hasn't yet been installed? I asked him via email but haven't heard back. Should I download it again and this time save the Install OS X Lion to the thumb drive with Disc Utility? Why can't I find it? What if I wanted to uninstall it and go back to 10.6?
MacBook Pro, Mac OS X (10.6.8)