Can folks help me identify what steps I should take to extend the life of our old 15" MBP (from late 2006, 2.33GHz Core 2 Duo). Cosmetically, it's in good condition (although the power button has "collapsed" a bit). It has 3GB of RAM and the original 120GB HD. Right now running on Snow Leopard/10.6. It's really slowed down as of late, and I've needed to repair disk permissions with some frequency, so I'm thinking of the following: -Do a clean install of Snow Leopard (last OS DVD I have), and perhaps update the OS to Lion (10.7, which is the latest OS that will run on this machine) if that would help. -Replace the HD, although for what I would be using this machine for, I'd go with a 320GB drive (not a SSD). Is there anything else? Is there a diagnostics program I can run on the machine to determine whether there are more significant issues with it? Many thanks in advance.