It'll depend on other specs than RAM, such as CPU speed and graphics card. For instance my laptop has 4GB RAM, but a mere 1.3GHz (albeit dual core) with integrated graphics makes it run Dolphin with an unplayable amount of lag.
But if it's not working at all, it might be something else (especially if it used to before). Can you describe what happens when you open it? Does it open at all, give an error message, etc?
But if it's not working at all, it might be something else (especially if it used to before). Can you describe what happens when you open it? Does it open at all, give an error message, etc?