Hi I have a 2009 17" MacBook Pro (2.8 GHz Intel Core 2 Duo) with 4 GB of RAM running Mac OS X 10.7.5 It has fairly recently started running slower and slower. I have spoken extensively to Apple support who couldn't explain it - other than advising me to keep the hard drive half full - and the slowdown all seemed to follow an OS X upgrade a year or two ago. For example running Firefox seems to cause noticeable lags, also heavier apps such as Lightroom, iPhoto and Photoshop Elements cause problems. It soon becomes ver frustrating running these apps. I have moved most of the labour intensive tasks (image and photo processing) off on to another mac, but I still use the Pro for most routine work tasks such as Mail, Office, Skype etc. I just wondered what would be the best ways to give the Pro a little shot in the arm and maybe another lease of life without spending too much? Eg a RAM upgrade, or adding an SSD, I don't know which would be most effective (if any). Also, I bought the unit second hand with its optical drive removed and had planned to install something inside but never got round to it. Any idea if a modern SSD would fit in this space - eg a Samsung 840 series? I am ideally looking for beginner friendly upgrades... I am not worried about voiding the warranty, as it is history, but I don't have much experience opening computers and changing parts (successfully!) Thanks in advance!