RE: controller won't initialize
Welcome to R/C !
I have had my G2 copy since it was released several years ago and have installed it on several computers without the problem you describe.
Depending on your transmitter interface (game port, USB), it sounds like a hardware problem to me (guessing). I would also make sure you are on the latest release by using the 'Realflight Control Panel' and clicking the 'Online Updates' button (if you haven't already).
Also, if the driver loaded correctly, you should be able to use the Windows Game Controller utility to help diagnose the problem. To get to the Game Controller utility (if XP), Click 'Start', then 'Control Panel', then 'Game Controllers'. From the 'Game Controllers' utility, you should see 'Realflight_ControllerW2K'. Seeing it in the list will prove Windows has loaded the driver. This does not mean it loaded it correctly at all, but at least you will have the knowledge that your install did try to load it.
If these few things do not help, you can always call Knife Edge software, or Great Planes to try and fix the problem. Course, all of this advise is dependant on your copy of G2 being registered. If this doesn't help, post back and I will tell you how to check the controller with some other utilities.
Hope this helps some anyway...
CJ