We claim the ornamental design for a computer, as shown and described.
FIG. 1 is a front perspective view of a computer;
FIG. 2 is an enlarged view thereof taken along the line 2-2 of FIG. 1;
FIG. 3 is a top plan view thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is an enlarged view thereof taken along line 6-6 of FIG. 5;
FIG. 7 is a right side view thereof; and,
FIG. 8 is an enlarged view thereof taken along line 8-8 of FIG. 7.
The dash-dash broken lines in the drawings are environmental lines which do not form part of the claimed design. The short dash-long dash lines are boundary lines which do not form part of the claimed design.