I assume it's an electric oven and grill. The oven and grill are often two different elements but in one unit. So it is possible for one element to burn out (i.e the oven), whilst the the grill remains intact. A new element for my Hygena was around �35.00 all told online.
as mortartube says,the oven element might have burnt out,they are quite easy to replace,a couple of nuts and 2 wires,take the old one off,and take it with you to match up,at the shop,ours has gone a couple of times,even christmas day once,so i allways keep a spare one now.