Dishwasher leaking.

Question

I was supplied a flat seal ring of about 100mm dia., 10mm wide & 1 mm thick for the machine when I bought the house. Water on the floor tells me something underneath is leaking for the first time. The machine is about 10 yr old and in very good order .This seal could be the problem so before I go getting service personel in I'd like to know if replacing this and the door seal are jobs a careful handyman can do ?