If you are talking about night photography as in taking a night landscape, then generally speaking, no you don't need a flash for that. All you need is a tripod and a long exposure (hence the tripod). Note that all flashes have a maximum range of coverage and hence its basically useless in such situations. If lets say you want to light up a foreground (be it a person or some other subject) when doing night photography, then, yes, you might want to use flash for this purpose.
Ok, the beep in the X700 goes on when your shutter speed setting falls below 1/60s (or is it 1/30s). That is to say, it is no longer recommended to handhold your camera and hence you have two options : put on a flash or use a tripod (or both), or even ignore the beep but that is another story altogether.
Anyway, what do you mean by nothing happens?
