The ornamental design for a microwaveoven, as shown and described.
FIG. 1 is a front perspective view of a microwave oven showing my new design;
FIG. 2 is a front elevational view of the microwave oven shown in FIG. 1;
FIG. 3 is a rear elevational view of the microwave oven shown in FIG. 1;
FIG. 4 is a right-side elevational view of the microwave oven shown in FIG. 1;
FIG. 5 is a left-side elevational view of the microwave oven shown in FIG. 1;
FIG. 6 is a top plan view of the microwave oven shown in FIG. 1; and,
FIG. 7 is a bottom plan view of the microwave oven shown in FIG. 1.
The broken lines immediately adjacent the shaded areas represent the bounds of the claimed design while all other broken lines are directed to environment and are for illustrative purposes only; the broken lines form no part of the claimed design.