Hi, I have a mid-2007 MBP 2.2 GHz Intel Core 2 Duo with 2 GB of RAM. My computer has slowed down quite a bit lately, so I'm considering a new MBP or MBA. I know that a MBA will be a downgrade in terms of processor speed, however, I wonder what is making my current computer slow, ie, will I feel the difference if I get a top of the line MBA. I get the spinny beachball all the time now, whenever doing multiple applications at once. My MacStatPro widget usually says I have about 10-30 MB of "free memory", which seems low compared to my 2 GB. So why is my computer slow? RAM? CPU? Something else?