I have a mobility scooter and need an urgent answer?

The scooter been sitting for about two years and I plugged it in and it will not charge.
Do I have to buy another battery or get the one I have charged before plugging it in. Do it mean the scooter is no good cause it been sitting too long?

Sounds like the battery is dead -- it happens. But, since it's been dead for a long time, make sure you give it plenty of time to charge, since you're basically starting from zero. If it still doesn't work, it means it's time for a new battery.