Return Rights On Used Car Can I Return My Newly Purchased Used Car W/o Being Sued?

Can I return my newly purchased used car w/o being sued? - return rights on used car

2/10/2007 I bought a car about 1pm. The next day, 2/11/2007 at approximately 7.30 clock, stopped the car runinng. Can I get the car without another car from them? Do you want my deposit back and my work? What are my rights as a buyer of used cars?