Hi:In terms of proving the machine, if you have any kind of installer and the main drive is blank, just plug it in and fire up the machine. It should chime and look for the installer. If it finds it, there's most of your questions answered.
I think I can pinpoint where the problem is. It is the track pad and keyboard. I managed to borrow a 2012 MacBook Air that I can use OS X Lion USB installer to install OS X Lion on a Sata Hard disk via USB to Sata adaptor. I put this hard disk into the 15" 2011 MacBook Pro, it can boot all the way to the login screen, but both the track pad and keyboard are not responding, so I was stuck. The track pad and keyboard hardware seems OK, connectors are also in good shape. Don't know why they are not working. SMC and PRAM reset did not help.