I don't get it. When I installed Firefox on my 2.4 Ghz Aluminum iMac, it mounted what looked like a harddrive with the Firefox logo on it (in pic). Whenever I try to eject it and relaunch, I first have to click on the Firefox logo in the window (in pic), which mounts the "harddrive". I don't get it; the same thing happens when I launch Azureus, or iSquint, or any other application from the internet. I don't get it; why is that harddrive logo there? Plus, when I try to get rid of the .dmg files when the program is in use, it won't let me. What's going on?