A possibility: is your girlfriend using an Apple Remote Control for her iPod or her Apple TV? If so, this would interact with her computer as well. If that's a problem, Apple Menu --> Preferences --> Security --> Disable Apple Remote Control for this system.
You're right, AT&T has horrible coverage. No, you cannot at this point use it on Verizon, a CDMA technology network (iPhone is GSM). It was almost enough to make me give up on iPhone, but in the end I couldn't do it. Depending upon your area, other GSM networks might be a solution for you if you are willing to jailbreak and unlock your iPhone. T-Mobile in the US was good when I used it; there are others in Canada and elsewhere.
The Apple Certified Tech's answer above is a good one, and maybe the correct one. An additional solution for me has been to download SMC Fan Control, a free add-on that will allow you to manually (or automatically) control the fan speed, and in additional will show you the temperature in your laptop. http://www.macupdate.com/info.php/id/230...
Forget plastic bags...I use a muffin tin, such as that used for baking, and put the screws from each step in successive muffin holes. When I reverse, I just back up the order.