The ornamental design for a notebookcomputer, as shown and described.
FIG. 1 is a perspective view of a notebook computer showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The dot-dashed broken lines represent a boundary of the claimed design and form no part of the claimed design. The dashed line showing of portions of the notebook computer is for the purpose of illustrating unclaimed portions of the notebook computer and forms no part of the claimed design.