Please tell what advice is here that is not to be listened to? My links go to Tab specific information forums. Are you saying that no one is to read xda-devs or MoDaCo? If so, then thanks for the suggestion but go stuff it. Actually, Google Maps is, in fact, available in the Android Market. Well done for stating the obvious but who ever said that Maps was not in the Market? The OP has problem with Navigate which is not in Market. What information do you have that Navigate is part of Maps? The information I have seen is that Navigate is part of the Os. Hence the suggestion to reflash if the problem is not related to Task Killer. How else to reinstall Navigate? I really would like to know so please tell us as there are other posters elsewhere who have the same problem.
Actually, Google Maps is, in fact, available in the Android Market.
QUESTION: how do I get this thing back to the way I got it from the store? Factory reset means resetting your SETTINGS to factory settings--it has nothing to do with reinstalling the software/firmware state. For that you would need to flash the ROM with the OS image or use Samsung's app that flashes the entire device firmware. If I'm not mistaken, there is a Samsung application called Odin that use a PIT (image file) for your particular device to restore everything to factory state. But I would HIGHLY recommend NOT doing this or only doing it as a very, last resort (i.e. you're already bricked).
QUESTION: how do I get this thing back to the way I got it from the store?