Welcome to this Band of Pirates . . . Pictures always help! Is the leak in the faucet or underneath the sink itself? Both require different advice.
If the faucet is leaking, Windows is on the right track. If the faucet is just old and worn out, like Neal, then it might need replacing outright.
If the water is coming from underneath (not the drain line) then the supply line or the shut off (angle stop) might be the problem. The drain line is another course of action.
Can't wait for your response!