How to fix a washing machine stuck on wash cycle

Hello! I have a Samsung Sensor Quick 800 front-loading washing machine. I'm not sure entirely how old it is as I inherited it from the person whose apartment I took over in Jan 2014. Earlier this year I moved and brought it with me but it has not worked properly since then - I suspect this has to do with it being bumped while moving. When I run any wash cycle it will rotate, fill with water, and add detergent as usual but the digital timer will not progress beyond 3 minutes from the start of the cycle and if left to its own devices the machine would never stop running. When I turn it off then switch it to the rinse & spin cycle sometimes it has the same problem but sometimes it works. Any advice on what may be going on would be helpful!