Quick question about Flight Simulator X.....

So I installed the game (which took forever) started to do good really liked it, then I had to go, when I came back to play it, its as if I never installed it, It wasn't there any more, I've done this many times, I install it, player it, then I can never find it again as if I never installed it, what should I do??? (oh ya when I go to my computer and hit uninstall or change programs, its there, I just can never access it.)