I am relative new back into the Macs after being a dedicated user of Windows machines. I have a 2011 iMac which runs smooth as silk at all times using some intensive applications (Safari, Mail, Photoshop and Lightroom). I upgraded this machine to 8Gb just so it would not hit a limit. I have never seen the Beach Ball on this machine. My work place is all Macbook Pros (and a few Airs). When I started less than a year ago I was given an early 2011 Macbook Pro 15. This machine worked well until I started to open lots of applications then I got the Beachball. When Lion came everyone was upgraded to Lion and since then the beach ball is. The MBP has 8Gb of RAM and the system lags terribly. I also have this issue where the screen saver activates ramdomly during use. the only fix I can find online advises to delete a file from library\preferences et etc but that does not resolve the issue. None of the guys at work know the cause or how to fix (IT department). Do you think a clean install would be the way to go, to get a quick resolution to the issue?