The ornamental design for a monitor for computer, as shown and described.
FIG. 1 is a front, right side, perspective view of a monitor for computer showing our new design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a top view thereof; and,
FIG. 8 is a bottom view.
The broken lines showing portions of the monitor for computer are included for the purpose of illustrating portions of the article and form no part of the claimed design.