I'm finally getting to the point of exasperation after about two weeks of using an iMac. The very "intuitive" way of working of macs is counterintuitive to me as a lifelong pc user. That said, I've run into several problems, but will only address in this thread the icon troubles I'm presently having. I somehow lost the Thunderbird icon, so I'm unable to open the applicaton. I had already been using Thunderbird for a few days and have setup all my email accounts. It was working really well. Now I cannot open the application, so after searching for answers in the web, and not finding any, I decided to click on the Thunderbird dmg file. I thought that when it opened it would recognize that I already have Thunderbird set up in this computer and would give me the chance to recover the icon, which I want to permanently show in the Dock. Please also advise how I can permanently attach an icon to the Dock. Unfortuntely , when I clicked on the Thunderbird dmg file, it didn't recognize that it was already set up and installed in the computer, so I canceled the installation. Oddly enough, now I have two Thunderbird folders but still no icon. Should I delete one of the folders ? I tried to find out what the file extension for an icon is in a mac, but couldn't find pertinent information. It seemed to me that if I searched for icons in my computer, I may be able to determine if the Thunderbird icon is still in there or not and then go from there. I don't want to start all over and set it up again with all my email accounts. I also want to find the Thunderbird icon and set it permanently on the Dock. If you have any suggestions as to which book to buy to help me make the switch and begin to understand and troubleshoot these kind of problems, please let me know. Your prompt assistance is much appreciated. Thanks!