Canon don't know what's in their own manuals! They may be right about it needing fixing - but they may not be, and you can check for yourself first.
Sure you can reset the camera to the factory defaults - it's easy. Turn the camera on, in either shoot or playback mode. Press the MENU button for over 5 secs. The message "Reset settings to default?" appears on the LCD. Select "OK" and wait while the progress bar shows. That's the reset done.
Then take the battery and card out for a few minutes, and reinsert, turn the camera on.
This method used to cure various problems with the G2.
It may help you - it may not. There is indeed a switch which senses the position of the LCD screen, so that you can use it either looking from the front of the camera, or flipped over in the back. Is it reversed left-right or up-down? I would have thought up-down was more likely if it is the switch that has failed.
Try it. Good Luck, Nigel