hi again

So I am using the selector tool to move a lined diagram and i just want to click on it and move it around but I am having to click on the corner and hold and drag over the while object then only SOMETIMES does it let me move it! how can i keep it as one and move it? It's driving me nuts!! its probably something simple but ive tried joing objects? and copying objects then pasting to see if it moves as a whole then, but nope, it dosnt. help please