I have had chronic "buggy" issues with my mac. Here are some examples: - When I open a new window (ie. double click on a Word or pdf document from the finder) it will open behind other windows. - When I click on a window that I want to work on, it won't come to the front, I have to click on other windows in front of it then click on the window I want to finally get it to the front. - In Finder if, for example, I click on a file to re-name it, the renaming box appears elsewhere on the screen - not in the spot that I clicked. Also, if I am moving a file from one folder to another, the folder I want to move it to often won't highlight when I am hovering on top of it, but when I am elsewhere on the screen (it's as if what is showing on the screen is not aligned with where the mac thinks things are located on the screen). This is fairly a clearly a software issue. I'm a relatively sophisticated user but not a tech master. These problems started with a 2009 mac mini. They persisted when I migrated over to my 27" iMac. This has been increasingly frustrating and can't find any posts anywhere describing similar issues. Any help welcome. Thanks.