Hi, as a new user I have a few questions: 1. Is is advisable to turn on the firewall? I did, and now every time my computer boots and Skype loads, it asks to be accepted. Is there a reason why the setting doesn't last more than one session? 2. My Windows laptop needs to have the hard drive defragmented periodically - is that applicable to OS X? If so I wasn't sure where such a program is located (if it is part of OS X). 3. Also I don't see anything comparable to Add/Remove Programs in the Windows Control Panel. I know I can delete an application by dragging its folder to the Trash - but would there be remnants of the program elsewhere that need to be removed too? Thanks.