The ornamental design for a computermonitor, as shown and described.
FIG. 1 is a front perspective view of a computer monitor showing our new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a rear perspective view thereof.
The short dash-dash broken lines that are immediately adjacent the shaded areas define the bounds of the claimed design while all other short dash-dash broken lines are directed to environment only, it being understood that the broken lines shown throughout in the views form no part of the claimed design.