I have a 2012 MBP non retina. Approx 18 months old. 4GB RAM, 500 GB hard disk. OS 10.9.4 It is mainly used for email, web browsing and holding iphoto/itunes libraries, and occasional Skype/facetime. So no unusual applications or heavy use. For reasons unknown, it has all of a sudden started running very slowly, taking forever to be able to carry out the smallest task (opening an application, an email, web page, any file, even to select a drop down menu in the finder). This results in the spinning beach ball every time while I wait an eternity. I have restored the entire disk from a backup from approx 2 weeks prior, when everything was running well. I've cleared caches, reset PRAM etc etc. Is there something I'm missing here or is it a hardware problem? I think the memory usage is excessive, over 3 GB in use with no applications launched.